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CONTRIBUTOB&

H. W. ZIELER
J. M. LEONARD
GLENN H. PICKET!
JOHN T. MOSS, JR.
KARL A. BARLEBEN, JR.
JOHN P. GATY
ELBERT M. LUDLAM
MANUEL KOMROFF
LINCOLN K. DAVIS
A. LAURENCE DUNN, D.D.S.
GILBERT MORGAN
RUDOLF H. HOFFMANN
A. L. LUGN
ELLSWORTH C. DENT
JOHN W. VANDERCOOK
JAMES A. BARNES
FRANCES W. BINKLEY
JOHN N. HARMAN, JR.
ROWLAND S. POTTER

THE
MANUAL

A Manual for the Amateur and Professional
Covering the Entire Field of Leica Photography.

WILLARD Dv MORGAN
HENRY M. LESTER
and Contributors

MORGAN & LESTER, PUBLISHERS 1 Q O *7

100 EAST 42ND STREET, NEW YOHK JiWV//

Fir&b

Second Edition [

First Printing December 1936

First' 'Printing/ August 1935 -
Second Prmtiiig' ^p^emb.er J535
Third Printing August*

Willard D. Morgan
Henry M. Lester

, - r(

All rights reserved in all countries. No part of this book
may be reproduced or translated in any form without
permission in writing from the editors and publishers.

Printed in 0.S.A, By Wagner Printing Co., Inc., New Y<

ACKNOWLEDGMENTS

The Editors wish to express their appreciation to all
those who have assisted in the compilation of this work :

Contributors

of chapters, and the many friends working with the
miniature camera who have submitted photographs and
helped to formulate the scope of this Manual

Barbara Morgan

for planning typographical and montage arrangement

Bnth Lester

for collaboration in the editing of the volume.

TABLE OF CONTENTS

Before We Press the Button 7

by Manuel Komroff

An Introduction to Leica Photography 17

by Willard D. Morgan

A New Camera for New Interpretations. Why Specialized
Chapters?

PART I -BASIC LEICA TECHNIQUE

CHAPTER 1. Leica and Its Auxiliary Equipment 23

by Willard D. Morgan

What to Photograph with a Leica. Know Your Leica.
Your Beginning. How to Make Your First Leica Picture*
Models F and G Leicas. Interior Mechanism of the Leica.
Loading the Leica Film Magazine. Earlier Leica Models.
Leica Accessories. Vidom Universal View Finder. Wide
Angle View Finder. Direct View Finder. Wintu Angle
Finder. Sunshades and Their Use. Slow Timing Device.
Rapid Winder. Protective Cases. Flashlight. Single
Exposure Leica, and Film Holder* Summary.

CHAPTER 2. Leica Lenses 49

by H. W. Zieler

The Iris Diaphragm. The Miniature vs. Larger Cameras.
Depth of Focus and Eelative Aperture. Depth of Focus
scale. Exposure Variations. Perspective and the Various
Leica Lenses. The 50mm Lenses. Other Leica Lenses.
Proper Care of Lenses. Front Lenses.

CHAPTER 3. Color Filters 81

by Henry M. Lester and Karl A, Barleben, Jr.

When Filters Should be Used. Color Sensitivity Charts.
Color Balance correction of Contrast. Making Your Own
Filter Tests. Filter Factors. Choice of Film and Filter.
What Filters to Use. Filter Factor Table.

CHAPTER 4, The 35mm Film— Its Selection, Exposure.

and Development __..__ 97

by Henry M. Lester

Part I — Film Selection

Sensitivity to Color. Speed of Emulsion. Graininess.
Contrast. Latitude. Panchromatic Emulsions. Ortho-
chromatic, Special, and Color-Blind Emulsions. Reversi-
ble and Infra-Red Films. When to Use a Certain Film.

Part II — Film Exposure

Exposure Meters. How to Use an Exposure Meter. Ex-
posures Without a Meter. Photoflash Exposures.

Part III — Film Developing

Development with Relation to Exposures. Developing
Equipment. Developers. High and Low Energy Devel-
opers. Compromise Developers. Temperature. Agita-
tion. Short-Stop and Fixing Bath. Washing and Drying
the Film. Steps in Developing a Film. Reticulation.
Newton Rings. Storage. Film Cleaner. Reducing and
Intensifying Leica Negatives.

CHAPTER 5, Making of Enlarged Negatives:

Three Methods __133

by John N. Harman, Jr.

CHAPTER 6. Your Own Leica Darkroom 137

by Willard D. Morgan

The Darkroomette. A Model Darkroom. Bathtub Finish-
ers. Stocking the Laboratory. A Two Room Laboratory.

CHAPTER 7. Enlarging and Contact Printing 145

by Willard D. Morgan

Selecting the Equipment. Valoy Enlarger. Focomat
Enlarger. Accessories. Making the Actual Enlargements.
Estimating Print Density. Printing Control During
Enlarging. Photoflood Bulbs. Contact Printing.

CHAPTER 8. Enlarging Papers and Printing „ 163

by Elbert M. Ludlam

Choice of Paper Stocks and Surfaces. Tone Gradation.
Fast and Slow Projection Papers. Contact Papers. De-
velopment. Exposure. Short-Stop. Fixing. Hypo Test.
Drying. Ferrotyping. Toning. Spotting. Presentation
of the Finished Prints. Embossing Prints.

CHAPTER 9. Copying and Close-Up Photography ___ 187

by Willard D. Morgan — Data Tables by Henry M. Lester

Importance of Small Object Photography. Accessories.
Sliding Focusing Copy Attachment. The Extension Tubes.
The 135mm Lens Mount. Data Tables for Extension Tubes
Used Directly on the Leica. Tables for Extension Tubes
and Formulas. Avoiding Vibration During Copying. Criti-
cal Focusing with 30x Magnifying Glass. Focusing by
Measurement. Fixed Focusing. Illumination. Exposure

Time. Films Used. Developing. Filters. Auxiliary
Reproduction Devices. 250 Exposure Leica.

CHAPTER 10. Making Leica Positives for Projection 221

by Willard D. Morgan

What Makes Good Positives. The Two Positive Printing
Processes. Contact Printers. Eldia Printer Directions.
Making the Leica Glass Positive. Projection Paper for
Testing. Mounting the Finished Glass Slide. Film and
Glass Slides by Projection. Combination Printer Direc-
tions. Belun 1:1 Copy Attachment.

CHAPTER 11. Projecting Leica Pictures 237

by Willard D. Morgan

Equipment Available for Projection. Table of Screen
Distances and Areas. Titles for Films. Storage.

CHAPTER 12. Stereoscopic Photography 249

by Henry M. Lester

The Stereo Equipment. Filters. Sunshades and Film.
Stereo Color Pictures. Protecting the Stereos. Using
Two Cameras. Making of Stereo Paper Prints.

CHAPTER 13. Panorama Photography 1 257

by A. L. Lugn, Ph.D.

Equipment. Composing the Panorama. Panorama Tricks.
Making the Pictures. Printing. Assembling and Mount-
ing the Finished Panorama.

CHAPTER 14. Natural Color Photography 265

by Henry M. Lester and Rowland S. Potter

Kodachrome. Speed and Exposure. Daylight and Arti-
ficial Light Filters. Viewing and Projection. Stereo-
scopic Photography in Color. Making of Paper Prints.
Three Color Separation Negatives. Chromatone Process.
Wash-off-Eelief Process.

PART II — LEICA IN SCIENCE AND EDUCATION

CHAPTER 15. The Leica in Visual Education 275

by Ellsworth C. Dent

Educational Use of Pictures. The Leica Camera. Spe-
cial Subjects . . . Agriculture . . . Biological Sciences . . . Lan-
guages. . . Geography. . .History . . .Industrial Arts . . .Ar-
chitecture. . .Physical Training. . .Physical Sciences.

CHAPTER 16. The Leica in Historical Research 295

by James A. Barnes* Ph.D.

Obtaining Complete Historical Record Pictures. The
Research Equipment. Economical and Time Saving.

CHAPTER 17. Copying Books and Manuscripts 301

by Frances W. BinJcley

Actual Working Methods. Illumination. Films. Making
and Using Film Copies... The Clerical Side. Copying
Mistakes and Their Remedy.

CHAPTER 18. The Miniature Camera for Miniature Monsters_™._309
by J. M. Leonard

Catching the Insects. Equipment. Photographing in the
Field. Selecting the Correct Photographing Angle. Bring-
ing Home the Catch. Mounting the Insects. Lighting.
Ultraviolet Light. Equipment for Indoor Work. Photo-
graphing at Home. Exposure and Development.

CHAPTER 19. Photomicrography with the Leica Camera _____ 331
by H. W. Zieler

When to Use the Leica for Photomicrography. How to
Adapt the Leica to the Microscope. Photomicrography of
Living Matter with the Micro Ibso Attachment. Gen-
eral Photomicrography with the Sliding Focusing At-
tachment. Obtaining Critical Focus. Amateur Photo-
micrography. Selecting the Microscope. Illumination
Apparatus. Magnification and Resolving Power. Light
Sources. Filters and Films. Exposure.

CHAPTER 20. Dental Photography and Photography of

Small Objects ^357

by A. Laurence Dunn, D.D.S.

Equipment Required. Making the Photographs. Focus-
ing. Transillumination of Teeth. Photographing Re-
flected Images. Determining Exposures. Importance of
Keeping Accurate Records.

CHAPTER 21. The Leica as an Ophthalmic Camera 371

by Henry M. Lester

Equipment. Importance of Focusing. Illuminating the
Eye. Flashlight Eye Exposures. Leica for Clinical Pho-
tography. Use of the Placido Disc. Portraits of Patients.
Smoke Box Photography.

CHAPTER 22. Infra-Red Photography _™_....387

by John P. Gaty

Infra-Red Films. Differences in Infra-Red Values. Infra-
Red Photography in the Field of Medical Research...
Criminology. ..Photomicrography. Exposure and Filters.
Hypersensitizing the Film.

CHAPTER 23. Astronomical Photography with the Leica ..397

by Lincoln K. Davis

Equipment. Photographing Through a TelescoDe.

Ill — THE IN

CHAPTEB 24. Candid Photography with a Leica 405

by Rudolf H. Hoffmann

The Scope of Candid Photography. Selfconsciousness.
Candid Photographs in Industry. Candid Photography Not
Limited to Any One Particular Field. Equipment.

CHAPTER 25. Stage Photography 421

by Glenn H. Picket!

Lenses for Theatre Photography. Film and Hypersensi-
tizing. Picture Positions in the Theatre. Judging Ex-
posures. Slow Exposures. Developing the Negative.
Human Interest Photos.

CHAPTER 26. The Leica in the Hollywood Studios 431

by Gilbert Morgan

Location Scouting. Technical Reference Photos. Make-
Up and Candid Photos.

CHAPTER 27. Aerial Photography 439

by John P. Gaty

Aerial Compared to Ground Photography. Leica as a
Profitable Aerial Camera. Starting Your Own Aerial
Photo Business. Controlling Perspective by Lens Selec-
tion. Making the Preliminary Ground Survey. Filters for
Different Visibilities. Exposure. Infra-Bed Photography.
Films. Preventing Vibration During Exposure. Photo-
graphing From Transport Air Liners. Your Personal
Airplane. Aerial Photos at Low Altitudes. Equipment.

CHAPTER 28. Leica Photography in the Tropics 463

by John W. Vandercook

Equipment. A Dehydrating Method. Developing the Film.

CHAPTER 29. Photomurals with the Leica 469

by John T. Moss, Jr.

Relation of Photomurals to the Architecture. Physical
Limitations of Size. Subject Matter. Composing the
Photomural. Grain and Viewing Distance. Technical
Photomural Procedure.

INDEX 482

WE THE

MANUEL KOMROFF

The world is large and filled with many things. It is difficult
to get acquainted with so much. Existence seems to be crowded.
It is hard to feel at home in a place so full — so crowded with joys
and sorrows, dreams and hopes, as well as the multitude of objects
that pour like an avalanche into our lives. The products of the ma-
chine age alone form a Niagara that seems overpowering. There is
little time for leisure, and work seems the currency of our present-
day life. But in spite of all this, nature continues to grow and unfold
its loveliness.

Beauty is fearless and stands proudly beside the blast furnace or
the dynamo. These monsters do not disturb her. She holds mys-
teries greater than anything done by the work of man. She was
here long before the machine intruded upon our world, and she will
remain long after the last cogwheel stops its grinding whirl. Thes<3
two powerful forces stand side by side. Man must bow in reverence
before it all. It is wonderful to be able to see and know a few things
that are around us. And it is not possible to know more than a very
few.

This idea has often impressed me. It is a little thing, but it is
something I would like to record. I would like to show my friend a
symbol of these two forces that exist side by side in the crowded
world we live in. Somewhere I will find a little white flower growing
beside a black factory chimney. It will be worth recording and
I will touch a button and the hard cold and uncanny eye of the
modern 'camera will embrace the idea. I will take home a record of
what -has been in my mind. I will want to show it to my friend so
that he can see at a glance what I am thinking about.

I am thinking about the whole big world and our little lives.
About great dynamos whose force man can control and a little white
flower, growing beside them, which soon must wither and die, a
force that man is unable to control I am thinking of animals and
vegetables and minerals and how all things fall into these three
kingdoms to form the face of society. And I am thinking that all
these things exist only as a kind of reflection . . . and we see
them only as something that is projected on the mirror of the mind.
This mirror is a very mysterious and a very important thing. It
controls imagination and it has in it something that enriches our
lives. .

My friend sends me a snapshot of a white horse frisking across
a field against a dark stormy sky. Before he pressed the button
he used the mirror of his mind. It is a fine picture indeed, and I
compare it with the old dray horse that I once photographed in the
streets of New York. My picture shows a poor beast — heavy, worn,
sleepy but very patient and most reliable. The pictures are different.
But then our pictures are always different. Our minds are different,
our eyes are different; our lives, experiences, and emotions have all
been so very different. And even if we both photographed the same
flowers or the same machine, our photographs would be quite different.

Both my friend and I know something about the technical side
of photography. We both understand that the machine we are using
is very flexible and most adaptable. We know a few of its limita-
tions and some of its possibilities. We have chosen this very special
type of machine that we use because of its extreme flexibility and
because we believe that a machine can become an instrument of
expression. A fair amount of knowledge and a sympathetic feel ins
can convert a mechanism into an instrument for expression. An
artist would use a brush, but here we have chosen a machine to
express something that is reflected on the mirror of our mind.

I am anxious to show you some of these reflections, to show you
what T see in an animal, in a plant, or in a metal structure. I realize
the power of visual perception, and I know that I can tell you a good
deal with a small photograph, for I do not trust words too much.
And I am also anxious to see what you have to show me. I am eager
to learn about the world that you live in and compare it with the
world that 1 know. They are the same, and yet they are strangely
different.

A friend has just sent me a little picture that he has snapped
of a murderer in Eussia being led to prison. He is an ugly fellow,
and brutality is written over his face. There is something creepy
and loathsome about him. But he is not unlike a murderer in Aus-
tralia, or France, or America. I see now by that little picture what
a slight difference there is between them. And another friend has
just sent me a photograph of lotus flowers floating in a garden pool
in China. It is indeed very beautiful. But some of our own flowers
are also beautiful. They also sprout and unfold, and in time they
wither and die.

How alike things are in different parts of a large world. Brutal-
ity and ugliness exist in all places. And beauty is there also. But still
there seems a little difference, and it is this difference which is quite
fascinating. A Russian murderer and a murderer from Texas are
both vile creatures, and we look at their pictures side by side and we
compare the likes and the dislikes. And some of the flowers that
grow in China are very different from our own, and we want to see
more and more. There is interest in ugliness and there is pleasure
in what is beautiful. So full is the world. And many things are
so alike and yet so different.

Water Lily

Yasuo Kuniyoshi

The modern lens in the hands of a sympathetic and under-
standing person is an all-seeing eye whose glance pierces deeply into
surprising recesses of nature. It traps a wealth of detail and lays
bare great wonders. It often reveals things that the eye cannot see.
An athlete jumps over a bar, we press a button, and in an instant
that cold matter-of-fact crystal eye has caught him in mid-air. We
are surprised. A horse runs at a gallop, and his four legs seem very
strange indeed. The eye has failed to see it, but the camera has
caught something that must have been there.

And here we find some oil on the surface of water, and it catches
a glisten of light. What a beautiful design it makes! The human
eye can hardly take it in for it is moving rapidly, and what exists
at one moment is lost the next. But we have captured it in a flash,
and we have brought the record home to study. The water has now
emptied far into the sea, and the oil on the surface is also long gone,
but we hold a fairly good account of something that was once quite
beautiful, and we study it and stop to admire it.

The world passes before us in this strange one-way street called
time. The traffic is in one direction, from the present to something
that very soon becomes the past. It cannot be reversed. The hands
cannot turn backward. And the things that we see now we will
never see again. We are quite willing to allow the disagreeable to
pass and hope these moments may never return. But many things
are not disagreeable, and we would be glad to have a record of their
passing reflection.

And so, with the aid of that hard crystal eye, we trap a few
sensations that we know will never occur again. We snatch away a
picture of a fleeting image, an idea, a pattern that surely will never
be repeated, a horse making a record, a flower growing in the crevice
of a rock, strangers walking in the street, friends laughing with us,
scenes far away, and little incidents close to our hearts. All these
and many more.

But why should we want to hold a reminder of something that
no longer exists ? The universe is indeed a large place and very full,
and man is a very small creature. And the little pictures that he
bothers with seem so trivial. But man is a lonely creature. He lives
a life tormented by contradictions. He fears what he does not know,
and he feels at home with the things that he knows and understands.
His experiences are made up of little moments out of the past, and

Queen Mary

Elmar 35mm lens, f :6.3, 1/40, G filter, Du Pont Superior film.

Eudolf Hoffmann

these little moments, recorded on the mirror of his mind, have widened
his perception of life. And so he is at peace when he looks back
over the pages that he has recorded from his own existence.

Sometimes these pages are only vaguely in his mind, and some-
times they are pasted into an album. And that is why, no doubt,
my friend smiles when he shows me his little book of snapshots of
that never-to-be-forgotten camping trip he once made. What miser-
able snapshots they are; what wretched photography! He has since
Improved. But he smiles as we turn the pages because they bring
back something that is very pleasant. They bring back something
that he knows and understands. And he smiles because he feels at
home with these memories, and his troubled spirit seems at peace.
There is no better reason why the following pages of this handbook
should be read very carefully!

But before we press the button we might remember that the
two characteristic inventions of our age have been telegraphy and
photography. From the telegraph grew the telephone, wireless, and
radio. From photography grew an age of bad portraiture, silly snap-
shots, and vulgar movies. Eealism, that stark naked child of our
century, fared much better with the electrical inventions. The optical
inventions retained a hang-over from our dreamy romantic age.
Photographs were made soft and sweet. A bad school of fuzzy photo-
graphy held the stage for several generations. Perhaps the reason
for this is the fact that art is much more conservative than science.
A false notion in the mind of man can often be altered by a single
experiment, but his aesthetic sense, controlled mainly by his emotions,
is slow and difficult to change. Photography, although most startling
at first, was very slow to take its place in our realistic age.

In painting, the revolt against sentiment and tradition occurred
many years ago. Impressionism came like a blast and recorded a
new emotional sense; one which was more harmonious with our age.
And long before impressionism and our present-day school of candid-
camera photography, distinguished artists used the hard facts of
realty "as a subject for their art. Daumier, Goya, Gavarni, and Dela-
croix were only a few of the distinguished names.

Somehow or other it took many years for photography to see the
world in the light of these artists. It was stupidly slow. And yet it
held great advantages. These advantages are twofold: mechanical,
and psychological. Mechanically a photogra^ can be rapidly mul-
tiplied and easily enlarged or reduced. Psychologically it holds a

great advantage over many forms of expression, for a thousand
y/ords in the ear will often tell you less than a single glance of the
eye, and a photograph speaks in a language that needs no translating.
It is upon this psychological factor that a new form of newspaper,
printed mainly in pictures, has taken so great a hold upon a vast
public.

About ten years ago a definite departure took place in the field
of photography. A small precision camera made its appearance.
At first glance, it resembled a toy, but on close inspection it was
found to have those requirements necessary to become an instrument
of expression. It was flexible and could be brought into action
quickly. It had a very sharp lens, a good depth of focus, a rapid
shutter, and seemed quite complete. It also had several disfhret
advantages such as a crystal focusing device adapted from the range
finder used on guns — the only good I know the War to have ac-
complished— and it used a strip of regular motion-picture film. As
this film is procurable in all civilized parts of the world, and is made
with various fine emulsions, it seemed most desirable. With tins
little instrument forty pictures could be taken upon a single strip
of negative in rapid succession. This was a great advantage. All
in all, here was the instrument many had been waiting for. This was
the machine that could record something that came to the mirror of
[•he mind. For many it opened up a new field of expression. And
there were a great many in the world who found this a most natural
ruedium of expression, in fact the only medium that they were capable
of. Here was an outlet for pent-up visions. Here was a way tc
gay something eloquently for many who, up till now, had remained
inarticulate.

In the ten years that followed, this new field of photography
has rapidly come forward. Lenses have been made more rapid, film
stock much improved, and special methods for developing and en-
larging have been perfected. With the aid of numerous attachments
'for special work, the little instrument has extended its bounds, as the
pages of this volume testify, in a most amazing manner. All this in
ten years!

The original camera designed to do this type of work soon
found competition. Several are now on the market using motion
picture film and equipped with range finders and rapid lenses.
Except for a very few special things, this handbook applies equally
to all cameras in the miniature field.

The pages of this volume contain material and data taken from
the actual experiences of a group of experts, each a specialist in
his field. The information, data and formulas are the very latest
that have thus far been perfected. The methods of photography,
developing, printing and handling of camera, equipment and acces-
sories, are also the result of very practical experience. Beside this
are added some special chapters on Infra-Bed, Photomurals, and other
fields quite new to this branch of photography. All in all, these covers
embrace the most complete knowledge on this subject that is possible,
at this time, to present.

The editors have proceeded with a conviction that the traffic of
ideas was more important than merchandise. There are no secrets
aird "nothing that they know is withheld or covered up with an air
of mystery. They recommend no vast expenditure for equipment or
special accessories. But they do ask you to pause a moment before
you press the button and acquaint yourself with the instrument and
read these pages so that you may know what is to be known in this
new field of photography. Knowing is important.

Our age is distinguished by knowing about an infinite multitude
of objects. Our existence seems crowded with things. When we
select a few of the things about us, we display knowledge. Tf what
we select is pleasing, then we have added an aesthetic sense. And if
we compose what we have selected, then we extend the aesthetic sense
into something that has a meaning and design. Here creative pho-
tography begins. But now one more factor is required: a technical
knowledge. And here it is.

Swinging Steel

Peter Stackpole
15

Rope
16

Manuel Komroff

WILLARD D. MORGAN

In 1925 automobiles were on the verge of a metamorphosis into
streamlining, the familiar granite ware of our kitchens turned into
an array of colors, women smoked on the streets, modern architecture
was being championed by Frank Lloyd Wright, Le Corbusier, Eich-
ard J. Neutra, and others, a few startling photographs taken at
unusual angles appeared in advertisements, the movies were begin-
ning to talk, Eisenstein's Potemkin and other Eussian pictures
startled movie fans, and the vast majority of photographers were
making the same sweet pictures which their grandfathers made in
the horse and buggy days. Let me add here that while all this pic-
torial photography was good in its day and we have profited from the
experiences of these earlier photographers it is not sufficient for us
today. To continue with the romantic pictorial conceptions is like
painting a Eembrandt picture today, or building a Gothic cathedral
in the shadow of a New York skyscraper with all its modern steel
construction.

Into this teeming world of change there was introduced a small
insignificant camera, it looked like a toy, no photographer gave it
much of a second thought, true it bore all the stream-lining and
modern earmarks of the new age, yet how could such a thing which
used only motion picture film be used for serious photographic
work — it was called the Leica !

Here was a camera which came as an interpretation of the new
developments of the day. A camera which was destined to com-
pletely change the photographic conceptions of amateur and profes-
sional photographers alike. With the Leica it was possible to secure
pictures in places which were formerly taboo for the ordinary camera.
Now it is possible to go into court rooms, take actual performance
pictures in theaters, and photograph the passing American scene in
all its naturalness. During the intervening ten years from 1925 to
1935 the Leica gained thousands of users in every country of the
globe. Today the Leica is not only beginning its second great decade

but it is continuing to create new photographic uses and operate in
the hands of the beginning photographer as well as the professional.
Through the remaining pages of this book fundamental information
about using the Leica will be presented and at the same time addi-
tional chapters included to give glimpses into more specialized fields
where unusual Leica work is already being done.

A New Camera for New Interpretations

It may be true that a modern camera like the Leica in the hands
of a photographer who is still thinking from the angle of a 5 x 7 or
8 x 10 view camera will not produce anything very different. But
let us use our small camera in a way which will be in keeping with
its true functions. The larger cameras gave us the heebe-jeebees
when we took a dozen pictures or more because the film costs mounted
so rapidly. While with the Leica we are taking yards of exposures
on 35mm motion picture film at the rate of eight pictures per foot
of film which cost a few pennies. Instead of feeling the usual photo-
graphic cramps our small camera gives us freedom of expression, it is
our visual note book of passing events. A camera which can be
carried in the pocket and used daily has become a necessity like our
watch or fountain pen. In this way the Leica can actually enter
into our daily living and produce photographs which speak our own
language and not the expressions of past decades.

Therefore why make the going difficult by spending all our time
striving to make salon prints when the world is teeming with photo-
graphic subjects which can be collected through the lens of our Leica
camera. A collection of Leica pictures revealing the American scene
may have more interest and value than a few laboriously made salon
prints. Why not have more fun in making photographs and keep
the release button on your camera working overtime.

During the past few years I have had an opportunity to come
in contact with thousands of Leica camera users either personally
or by correspondence. I have been with them in their triumphs and
assisted them in their photographic troubles. World travelers have
brought me their pictures, leaders of expeditions have come for ad-
vice, and the beginning Leica photographer may ask about the best
film or developer to use. I have been in the operating rooms making
pictures with doctors, in the air with pilots who want to learn more
about this miniature camera, and in industrial plants showing how
the Leica can be used to secure pictures for advertising purposes or
for use in training salesmen.

Friends

Elmar 50mm lens, f:9, 1/40, Panatomlc film.

Rudolf Hoffmann
19

Out of such experiences I have gathered together the basic ideas
now being presented in The Leica Manual. Instead of writing all
the chapters myself I felt that a book on this subject would have
much more value if various individuals who were doing specialized
Leica work could present their own experiences. In this way the
present volume has been written and I am certain that it represents
something quite different from the usual photographic book. As a
reader you will find the very latest information, developments, and
technique, covering the entire field of Leica photography.

The majority of us are interested in what may be termed genera*
photography or the making of good pictures which relate to our own
lives. To this group I can say that they need not be frightened by the
immensity of the Leica field which is covered in this book. A thorough
understanding of the basic photographic principles is sufficient for making
all the pictures you can ever hope to print. You only need a Leica with
one of the 50mm lenses, an exposure meter, and a good fine grain film
to start with. With such a minimum of equipment you can easily make
all the pictures which may be classed in this field of general photography.
At first you can have a reliable finisher do your developing and enlarg-
ing. However, as your interest in miniature camera work develops you
will find that the real pleasure comes when you do your own finishing
work. As you expand your interests the more specialized chapters in this
book will give you valuable information which comes from the experiences
of other actual Leica users.

It should be noted that whenever possible the Leica accessories are
included in the chapters which relate directly to the use of these attach-
ments. For example, all the Leica lenses are thoroughly described in the
lens chapter, the various copying attachments will be found in the chap-
ter on copying, while the panorama equipment is in a special chapter
covering this subject. In this way the Leica Manual becomes a prac-
tical handbook for the Leica users who are interested only in general
photography as well as for those who are adapting their cameras for
more specialized work. Today you may be interested in photographing
only general scenes, while next month or next year you will become fas-
cinated with the possibilities in aerial photography or in adapting the
Leica to your special hobby or profession. The wealth of information in
this book makes it possible to adapt the Leica for use in practically any
photographic field.

Why Specialized Chapters Were Included

In addition to the more or less standard chapters covering the use
of the Leica a few chapters have been included covering more specialized
fields .such as Eye Photography, Dental, Photomurals, and Photomicrog-
raphy. Rather than devote many pages to repetition and a resume of the
camera accessories readers of this Manual will undoubtedly appreciate the
efforts of the editors to present new and fresh information covering the
fascinating field of Leica photography. A careful reading of these spe-
cialized chapters will reveal information which can be applied to general
photography as well as to the more specialized fields. In addition to
being an authoritative manual on the subject of Leica photography, we
want this book to serve as an inspiration to every reader by making
him aware of the new possibilities in miniature camera photography.

The chapter on Photomurals covers a subject which is entirely new
I'n the miniature camera world. Thus a careful study of this chapter
will reveal that photography may express itself in new forms with new
ideas in keeping with our more or less complex civilization. Why shouldn't
our photographic work interpret our own 'times instead of slavishly imi-
tating the work of past masters of the camera? The pictorial era in
photography which flourished from 1890 to 1925 gave us. . .atmosphere
...misty landscapes. . .labored compositions. . .imitations of the graphic
arts and oil paintings ... sentimental nudes reclining on rocks in lonesome
forests, and prints which had been worked on until they could not be
recognized as coming from their own original negatives.

Thus photography became muscle bound with the lavish rules
which had to be observed before the photographer hoped to have his
picture accepted in the exhibitions. Even to this day we find judges
of salons who still cling to the romantic days of photography and
discourage the new expressions which are rapidly developing because
such pioneers as Alfred Stieglitz, Edward Steichen, Eugene Atget,
Edward Weston, Maholy-Nagy, Man Ray, and others felt that pho-
tography is an art in itself.

The Editors wish to note in offering this second, revised edition
of the LEICA MANUAL that due consideration has been given to the
significant advances which have been made in the miniature camera
field. New natural color processes, new filters and newly compiled
authoritative data on filter factors, a new direct positive enlarging
medium, new accessories and lenses, revised and corrected formulas,
new information on enlarging papers — were incorporated into this
volume. In addition to numerous small revisions and corrections
made throughout the book it has been interspersed profusely with
new, fresh, and exciting photographs. Having sold over 17,000
copies of the LEICA MANUAL in fifteen months— the Editors are
bringing it up to date as the standard reference for all miniature
camera photographers. Copies of the LEICA MANUAL have found
their way into practically every corner of the globe, no matter how
remote or isolated.

PARTI

BASIC LEICA TECHNIQUE

Steel and Concrete
22

Willard D. Morgan

ITS

WILLARD D. MORGAN CHAPTER I

When we first look at the Leica camera many questions naturally
arise regarding its construction, operation, and results which may
be expected from its use. Such a small camera as the Leica requires
a special technique which is different from other cameras. After
all, any camera consists of a lens and a light-tight box containing
the film. From this basic principle many cameras have been devel-
oped, incorporating hundreds of different special features which
tend to make the operation of the camera more easily adapted to
special uses.

In the case of the Leiea, an 'entirely new photographic field was
entered with such a radical change in camera design that immediately
many old habits had to be revised in order to understand the possi-
bilities of miniature camera work. The Leica camera required the
use of 35mm motion picture film, the use of fine grain developers,
an appreciation of the value of short focal length lenses and their
possibilities in securing photographs which were radically different.

As the Leica camera was developed through the various succes-
sive stages from the early Model A to the Models B, C, D, E, F and
the present Model G- with shutter speeds from 1 to 1/1000 second there
naturally developed a tremendous interest and demand for informa-
tion bearing on miniature camera work. Such information assisted in
helping all miniature camera users to band together and work in this
new photographic field. In fact, many people using the Leica camera
actually belong to a fraternity "by-- themselves. Evidence of this fact
is to be seen in the numerous miniature camera clubs which have
recently been formed as well as the personal interest among small
camera users, and the large amount of space given to miniature
cameras in the photographic magazines.

In developing the technique of miniature photography, it has
been necessary to do considerable experimental work and also pro-
duce many written articles covering the important phases of this
type of photography which requires a technique unfamiliar to the

average person occasionally using a box camera. Naturally, the
users of other than miniature cameras may 'be confused upon their
first introduction to the possibilities of miniature camera photog-
raphy. They will hear discussions about this and that highly cor-
rected lens, resolving power, circle of confusion, depth of focus,
various different orthochromatie and panchromatic films with their
advantages and demerits. The religion of fine grain will be ever
uppermost.

Although the people who are actually using the miniature camera
are deriving immense pleasure from their particular work, it may be
that the outsider will look upon such a field as a chaotic world.
Miniature camera users will talk about enlarging negatives the size
of a postage stamp up to 16 x 20 inches or more. While many
workers in this field enjoy the experimental angle, it is true that over
90% of the miniature camera users are interested in simply produc-
ing good photographs. Most of us make our Leica enlargements
either the postcard size or the 5x7 inch size. Beyond this size, we
enter the field of salon prints or enlargements which may be used
for mounting and hanging in the home.

For example, a Leiea user in Indiana writes the following after
talking with one of the uninitiated miniature camera users :

"About 90% of the camera users of today are not interested in
wonders. They do not possess the skill of the expert. They are
interested in a camera that will perform well in the hands of the
ordinary man in the street, the man who is willing to pay the price
of a good camera but lacks the skill of an expert. Does the Leica
meet this condition? My opinion is that it surely does."

What to Photograph with a Leica

Photographing with a Leica can be one of the simplest and most
effective means of making a perfect negative. On the other hand a
Leica user can become -so involved with his camera, accessories, and a
multitude of ideas about miniature camera photography that he may
lose sight of the original idea behind the Leica. The Leica was
produced to simplify photography and make the actual use of this
camera so convenient that it would be indispensable. After all why
not use our Leica camera functionally and become familiar with the
many intriguing uses to which this camera may be applied.

Before starting to take pictures with our Leica let's stop a
moment and become familiar with the photographic possibilities
open to the miniature camera user.

Leica Equipment

1. Because of the small size of the Leica it can be concealed in the pocket
and later used for making pictures in practically any place where there
is sufficient light to make an exposure. You may catch the unposed
positions of people in a railroad waiting room, or the information clerk
carefully explaining some route to a customer. The theater, night club,
public gatherings, street scenes, and everywhere people meet there will
be pictures for the Leica user to make. Such photographs tell their own
story, and show in a moment that the photographer must have had a
miniature camera and worked quickly in order to make the exposure.

2. Use the Leica for making twenty or thirty successive portraits of the
same person and thus catch a more complete interpretation of character.

- These views will portray a wide range of interesting expressions instead
of the usual one-view portraits which are made with the larger cameras.

3. This same idea of making sequence pictures can be used for photograph-
ing children who are forever scampering about. Catch these colorful
expressions of the youngsters and arrange the resulting pictures in an
attractive series in your album.

4. When traveling with the Leica you will find that it is easier to take
many more than the ordinary number of pictures and thus give a more
complete record of your trip. With the cost of film so small there is no
reason why many hundreds of interesting pictures cannot be obtained,
even on a short trip of only a few days.

5. At the horse races, athletic events, yacht races, and other similar events
the Leica will fit into the occasion without being in the way and thus
take the edge off an otherwise glorious time.

There are naturally many other uses for the Leica. One of the pleas-
ures of owning this camera is to discover some of these uses for oneself
and thus satisfy one's creative instincts in producing something a little
different from "the boys with the big cameras". In this book the writers
have endeavored to present their photographic methods as well as to convey
some of the pleasures to those who are seeking new discoveries and a more
complete understanding of miniature camera photography. To begin with,
let's start with the equipment itself.

Know Your Leica

As the Leica has been constructed quite differently from most
cameras we should become more familiar with the important working
parts. Let's take a Leica in our hands and look at it ... wind and
release the shutter . . . set the speed dial at various stops . . . pull
the lens 'barrel out and lock it by a slight turn to the right . . . turn
the focusing mount of the lens and watch the images move out of
focus or into focus through the range finder which is coupled with
the lens . . . open and close the iris diaphragm of the lens . . .
study the depth of focus scale at the base of the lens mount . . . try
the slow shutter speeds on the Model F Leica . . . move the counting
dial to zero after winding the shutter . . . move the small lever
between the winding knob and the time setting dial to E or reverse
. . . pull up and turn the rewind knob, then push it back into posi-
tion and change the lever back to A or advance . . . adjust the com-

pensating eyepiece of the range finder for distances under 15 feet
. . open the baseplate . . . remove the take up spool and film
magazine . . . try loading and unloading several times before replac-
ing the baseplate . . .then go back to winding and clicking the
shutter, and at the same time focus on actual objects and imagine
that you are making actual pictures.

All this may at first seem complicated but once you have gone
through this routine the actual operation of the Leica will seem
extremely simple. You will become familiar with a new type of
camera which has been built to eliminate the usual amateur photo-
graphic troubles, such as double exposures, out of focus pictures,
under-exposures because of slow lenses or failure to stop rapid motion
because of slow shutter speeds.

To make Leica pictures it is not necessary to own the very
latest model camera with all the interchangeable lenses, filters, cases,
and a hundred other accessories which could be used. No, all this
equipment is for those who can afford it and also for use when they
have advanced to the point where more specialized photography is
required with the Leica.

Fig. 7 Leica Model F or G Equipped with 50mm f :2 Summar lens. Model
G Available in Chrome Finish Only

Your Beginning Leica Equipment

All you need as a beginning Leiea user is: a Leica camera
equipped with one of the 50mm lenses, an exposure meter, and

Leica Equipment

several rolls of film. With this outfit you can take thousands of
excellent pictures and never miss the use of additional accessories.
Many fine picture are still being made with the early Leica Models
A and C. The basic idea of the Leiea has never changed since the
day it was first introduced in 1924. Therefore it is unnecessary to
be disturbed by the haunting thought that it takes a fortune to
operate a Leica. On the contrary, once the camera is purchased the
operation cost is drastically cut when compared to the larger
cameras.

How to Make Your First Leica Picture

"When preparing to make your first Leica picture there are a
few important points to observe as follows :

1. Place the film magazine containing the unexposed film into the
camera after removing the base plate and take up spool. Figure
8 shows the position of the film when properly loaded.

Fig. 8 Dotted Line Shows Correct Position of Film when Loaded in the
Leica camera. M — Take up Spool, W — Film, D — Film Magazine

2. Check to make certain that the reversing lever, located between
the winding knob and the speed dial, is at A or advance. (This
lever is moved over to E after all the exposures have been made
and the film is to be rewound into the original magazine.)
Turn the winding knob and click the shutter twice in order to
pass the film which was exposed to the light while loading. Then
wind the shutter a third time and also set the counting dial at
picture number one opposite the small arrow. If preferred the
counting dial can be set at zero after the second wind of the
shutter. Then after the shutter has been released the camera is
ready for making pictures.

Determine the correct exposure with the Leicameter, Leicascop
or other reliable meter.

Set the shutter speed on the dial by slightly lifting and turning
to the proper position required. Before setting the shutter
speed turn the winding knob one complete turn. In the case of

the Model F Leica the slow speed dial is set at any desired stop
between 1 second and l/20th of a second after the top dial has
been set at 20-1 which represents l/20th to 1 full second on the
slow speed dial. When l/20th is to be used on the Model P set
both dials at the figure 20.

6. Full out the lens barrel and lock it into position by a slight turn
to the right, in case one of the 50mm lenses is in use.

7. Set the iris diaphragm to the proper opening which has already
been determined by using the exposure meter.

8. Secure exact focus by looking through the range finder eyepiece
and at the same time rotate the lens barrel back and forth until
the two images coincide. (The earlier Models A, C, and E Leica

Fig. 9 Rear View of Range
Finder and View Finder. Note
Magnifying Eyepiece on Range
Finder Adjustable for Sharp
Focus on Near Objects under
15 Feet When in Upright Posi-
tion

cameras do not have the built-in range finder with automatic
lens coupling as in the later models. However these earlier
models may be converted to a later model, or a separate range
finder may be used for determining the distances.) "When only
one image is seen through the range finder the subject is in exact
focus. Shift the eye to the right (when holding the camera hori-
zontally) and compose the picture through the view finder. When
you are ready to make the picture, press the release button
gradually and thus make the exposure. You have now taken
your first Leica picture !

9. Keep on taking pictures until you have used up the entire roll
, of 30 or 36 exposures. Try various shutter speeds, outdoor and
indoor views. Place your Leica in its case or in your pocket,
then see how fast you can whip it into action and at the same
time remember the points which, are essential for making" a
picture.

1. Determine the exposure

2. Pull out and lock the lens into position

3. Set the lens diaphragm stop

4. Turn the shutter winding knob one complete turn

5. Set the shutter speed dial

6. Look through range finder and determine focus

Leica Equipment

7. Shift your eye to the view finder and compose picture

8. Gradually press the shutter release button and make the
exposure.

10. Caution . . . When pressing" the release button with the fore-
finger avoid jerking the camera by abruptly pushing the release.
Instead, hold the finger on the release and gradually squeeze
the button down, similar to the gradual trigger squeeze which is
so essential to accurate shooting with a gun. Place thumb of
right hand under the base plate to counteract the downward
action of the forefinger. Wherever possible it is best to use
shutter speeds of l/40th or l/60th of a second or faster when
the camera is held in the hands, in order to avoid any possible
motion during exposure.

11. When you reach the end of the film roll the shutter winding
knob will not turn . . . don't force it and try to squeeze another
exposure onto the film. Instead, just move the reversing lever
to R and rewind all the film back into the film chamber. The
base of the release button will turn during this procedure and
will stop the moment the film pulls away from the take up
spool in the camera. The film magazine may be removed from
the camera after the winding has been completed and the
reversing lever moved back to A or advance.

12. Each time the shutter winding knob is turned, when there is
film in the camera, the rewinding knob turns in a reverse direc-
tion (counterclockwise), thus indicating that the film is properly
passing to the next exposure.

Loading the Leica Film Magazine

The standard Leica Film Magazine, sometimes referred to as
model B, has been constructed to hold about 5% feet of 35mm cine
film which is sufficient to make up to 36 double frame exposures, 24
by 36mm in size. This cylindrical magazine contains three parts :
the outer shell B1, the inner shell B2, and the center spool B3. The
guide groove on the inner shell and the pin inside the outer shell
opposite the safety spring, assist in opening and closing the film
magazine.

To assemble the magazine first insert the daylight film spool
into the inner shell with the tip of the film in the opening of the
spool chamber. It is a good plan to bend back the tip end of the
film in order to make it easier to pull the film out of the magazine,
and also to prevent the film from drawing back into the magazine
before loading into the camera. Next, introduce the inner shell with

spool into the outer shell with both rectangular openings together
and open. When the inner shell comes to a stop turn it to the left
or anti-clockwise until the safety spring clicks into the locked posi-
tion. Before the chamber is closed pull the film out several inches.
The film magazine can only be opened after the safety spring has
been slightly lifted and the inner shell turned to the left or clock-
wise. The inner shell is then withdrawn and the film removed
either in the daylight or in the darkroom, depending upon the film
packing used.

Fig. 10 The Model B Leica Film
Magazine.

B = Complete Spool Chamber Model B

B1 = Outer Shell

B2 = Inner Shell

B3 = Center Spool

B* = Spring of Center Spool

B5 = Milled Knob of Center Spool

B6 — Slots of Spool Chamber

BT = Knob of Spool Chamber

B8 = Safety Spring

The Outside Parts of the Models F and G Leica Cameras

1. Winding knob . . , one complete turn winds shutter, advances film to the
next picture, and registers one count on the dial 7 at base of knob.

2. Shutter release button ... with protective bushing which may be un-
screwed and a Wire Eelease screwed over the release button.

3. Shutter speed dial. . .for .setting speeds from l/20th to l/500th of a
second and time exposure. Dial 10 is used for setting the slower
speeds between l/20th and 1 second. Winding knob 1 must be wound

Lelca Equipment

one complete turn before setting speed dial 8. Once this dial is set it
need not be changed for successive exposures unless the shutter speed
is to be changed. Leica Model G has an additional shutter speed of
l/1000th of a second.

4. Clip... for holding Universal View Finder, Stereo Attachment, Level,
Reflecting View Finder, Angle View Finder, and other attachments. A
small engraved arrow on one flange of this clip indicates the shutter
settings.

5. Built-in range finder. . .which has an interior mechanism connecting
with the lens mount for determining correct distances and focus.

6. Rewinding knob. . .which is pulled up and turned to rewind the exposed
film back into the film magazine.

7. Counting dial... which automatically records each photograph taken.
On this counting dial there are two small lugs used for turning the dial,
anti-clockwise and against the direction of the arrow on the winding
knob, to the zero mark.

8. Counting arrow. . .indicating the number of photographs taken.

9. Reversing Lever. . .which disengages the automatic coupling of film ad-
vance and shutter mechanism when the exposed film is to be rewound
back into the film magazine. When this lever is set at R it operates
somewhat similarly to a clutch on an automobile by disconnecting the
camera mechanism. Keep the lever at A while making exposures.

10. Slow shutter speed dial... which turns to change the shutter speeds
between l/20th and 1 full second. There is also a time exposure setting
on this dial.

1. Winding Knob

2. Shutter Release

3. Shutter Speed Dial
4. Finder Clip

5. Built-in Range Finder

.6. Rewinding Kno

Counting Dial

Counting Arrow

Fig. 11

Reversing Lever.
A = Advancing Film

R = Reversing Film | I I 3.3. View Finder

10. Slow Speed Dial | 1^ Diaphragm Ring

11. Lens Focusing Lever

Outside Parts of the Leica Camera.

11. Lens focusing lever. . .which is pressed, to release the lens mount from
the infinity setting, and moved back and forth while the eye looks
through the range finder until the double image of an object comes
into focus and only one image is to be seen.

12. Knurled diaphragm ring ... with diaphragm markings which is turned
for setting the proper lens opening in the Summar f :2 lens. The 50mm
Elmar and Hektor lenses have the diaphragm settings on the front of
the lens mount.

13. View Finder. . .which includes the full area of the image registered by
the 50mm lenses. The Universal View Finder covers the picture areas of
the other Leica lenses.

The Interior Mechanism of the Leica

Fig 12. Diagramatical view of the Leica short base built-in range finder.
The two arrows point toward the object which will be in exact focus when
the image coming through the right hand movable prism is projected and
coincides with the image which is seen through the prism mirror on the
left. As the lens turns the base of the mount moves in or out and thus
moves the small lever which is attached to the right hand prism.

Fig. 13 Back cross-section view of the Leica showing focal plane shutter,
film, and all the actual working parts of the camera in cross-section.

Leica Equipment

Fig. 14 Looking down on cross-section view of range finder and view
finder housing. Note position of range finder prisms, the right prism is
moved by the bar which contacts the flange of the rotating lens mount.

Fig. 15 Top cross section view of the Leica showing position of the film
focal plane shutter, lens, and other working parts.

Daylight Loading and Unloading Film Spools

It is more convenient to secure Leica films already loaded in film
magazines or on an individual film spool which is inserted into the Leica
film magazine when required. The Agfa, Eastman, Gevaert, Mimosa, and

I/2

Fig. 16 Showing Method of Inserting the V2 Lock in the Earlier Leica
Models.

Perutz films are packed in complete magazines ready for instant use in the
Leica, These film magazines are daylight loading and unloading and greatly
simplify the film loading process. Figure 8 shows this type of film
cartridge in position.

Some of the earlier Leica cameras may require a slight change as
shown in figure 16 before this new type of film cartridge can be inserted.
The Vi lock is replaced by the V2 lock as shown in the illustration. The
change over is done by removing the two screws which hold the Vi lock in
position, and then replacing with the V2 lock. The V2 lock may be secured
from your Leica dealer.

The Du Pont Leica films are spooled with a black paper leader which
protects the film until it is loaded into the metal film magazine and then
inserted into the Leica. This film spool may also be unloaded in daylight
after the film has been exposed and rewound back onto the spool. Com-
plete directions for loading are packed with each roll of Dupont film.

When the film magazine is to be unloaded in the darkroom the paper
leader on the Du Pont film can be cut off after loading into the film
magazine. The film end is then inserted directly into the take up spool clip
without first winding all the paper leader on the spool before inserting into
the camera.

Occasionally one wishes to remove the film roll after half a dozen or
more exposures have been made. This may be necessary when a different
film is required or when some of the exposed section of the film is to be
developed. Before rewinding the film, note the number of exposures taken.
Then, after moving the rewind lever to R, raise and turn the rewind knob
until the film pulls loose. . .then stop in order to prevent the film leader
from going back into the film chamber. Remove the film magazine with
the two or three inches of the film leader still outside of the magazine.
Later this same film roll may be replaced in the camera, winding and
clicking the shutter as many times as necessary to move the exposed
portion of the film through the camera. The lens cap should naturally be
left over the lens during this process.

Fig. 17 Method of Cutting Film for Inserting into Magazine Spool

Leica Equipment

Fig. 18 Method of Cutting
Film End Which Projects
from Magazine and Inserts
into Take Up Spool when
Loading the Leica camera.

Loading Bulk Film

Bulk film may be purchased in almost any length from 15 feet to 1000
feet at prices ranging from 2 to 8 cents per foot. As the Leica will expose
8 pictures per foot of film it is an easy matter to figure out the amount of
bulk film required after allowing for the few frames which are lost at the
beginning and end of each Leica loading.

When loading the Leica film magazine with film from a large roll it is
necessary to carry out all operations in complete darkness, unless the proper
safety lights are used. In the case of fast panchromatic films complete
darkness is essential. Therefore it is best to practice loading the film
magazine in daylight with a short piece of film in order to become com-
pletely familiar with the operations. You can even shut your eyes during
this practicing.

When cutting film from the larger roll care should be taken to cor-
rectly taper the end of the film which attaches to the spool and also the
leader end which is partly cut away as shown in the illustrations. A Film
Trimming Guide is available for this cutting.

When the Film Trimming Guide is used for cutting the spool end of
the film, the guide is opened and the film inserted through the narrow
slot with the emulsion side down. Let the end of the film project slightly
beyond the end of the guide, close the trimmer and then cut the film as
shown in the illustration. Always make certain that no finger prints are
left on the emulsion side of the film.

Now place the other end of the five foot length of film into the Trim-
ming Guide as shown in figure 18 and make a longer cut in order to make
it easier to load the film into the camera later. It should be noted that no
cut is made through a perforation on the film edge. The Film Trimming
Guide has two pins which engage in the perforations and hold the film in
the proper cutting position. Place the film into the guide with the emulsion
side facing the two pins. The film ends can be cut with a scissors without
a Trimming Guide after a little practice.

Winding the Film

In order to make it easier to wind the film spool with fresh unex-
posed film a Hand Film" Winder and also a stationary Mechanical Film
Winder are available. The operation of these winders may be studied from
the accompanying illustrations. The Hand Film Winder is slipped into the
bottom of the center spool and engages the cross-pin for turning.

Fig. 19 Loading Film Spool by
Means of a Mechanical Winder.
Also for use with Model FF Spools.

Fig. 20

Winder.

Hand Film

The Mechanical Film Winder should be attached to a table or heavy
block of wood. A slit core receives the film spool ready for the film winding
process. After the film end has been fixed to the center spool, the film
should be wound tightly during the turning of the handle. Do not attempt
to pull the film and thus tighten the film already rolled on the spool. . .this
will produce scratches.

The Earlier Leica Models

Although the first Leica model was made by Oscar Barnack in 1914 it
was not until 1924 that actual production began with the introduction of
the Model A Leica without the interchangeable lens feature. This camera
contained all the Hasic features which are to be found in the latest Model F
Leica, with the exception of built-in range finder and slow shutter speeds.
During the ten years between 1925 and 1935 new improvements on the
original design created new models: Thus:

1. A camera with Compur shutter instead of the usual focal plane shutter
was introduced as the Model B Leica.

2. Interchangeable lenses brought out the Model C Leica (also known as
Model I).

3. A built-in focusing range finder adapted to couple to the various inter-
changeable lenses produced the Model D Leica (also known as Model II).

Leica Equipment

Fig. 21 The Pioneer Leica
Constructed in 1914 by Oscai
Barnack.

Fig. 22 The Model E Leica
with Fokos Range Finder.

Fig. 23 Detail of Leica Show-
ing Fokos Range Finder in
Position. Range Finder may
be Turned When Making New
Shutter Adjustments. .

4. A horizontal Short Base Range Finder and the pull-up type of rewind
knob identify the Model E Leica (similar to Model I).

5. An additional slow shutter speed mechanism, with speeds down to 1 full
second, was added to the Model D type and thus created the Model F
Leica (also known as the Model 111).

6. By the addition of a 1/1 000th of a second shutter speed the present
Model G Leica (also known as the Model Ilia) was produced.

Note. Outside of the United States the Model C Leica is known as
Model I, the Model D as Model II, the Model F as Model III,
the Model G as Model Ilia, and the Model FF as the 250 Ex-
posure Leica. It will be noted that the original Model A Leica
was simply known as the Leica Camera without a model number.

7. With the addition of film chambers to hold up to 33 feet of film 250
Exposure Model FF Leica was introduced.

8. Finally, the Single Exposure Leica was made to meet special re-
quirements.

Fig. 24 The 250 Exposure Leica Model FF.

Fig. 25 Loading the Leica Model FF. After Exposures Have Been Made
Film is not Rewound. Note Special Film Trimming Guide.

This brief summary of the various Leica models will be of special
value to many people who intend to "purchase ! either new or used Leica
cameras. The latest direction book which is supplied with every new

'38-

Leica Equipment

camera contains information about the operation of the Leica. This infor-
mation can be applied to all Leica models. Therefore it will not be nee-.
essary to reprint detailed descriptions and directions on these cameras.
One of the remarkable features of the Leica is the fact that it is possi-
ble .to convert any of the earlier models to the very latest model. This
fact alone is really a tribute to the inventor who was able to design the
basic features of the Leica so perfectly.

Leica Accessories

Along with the development- of the Leica there naturally came
the production of many accessories which served to extend the use
of the camera into many new photographic fields. With the introduc-
tion of various interchangeable lenses there was a need for the Vidom
Universal View Finder. The various enlargers made it possible for
the average amateur to make excellent enlargements from Ms Leica
negatives. Stereo, copy, micro, panorama, and other attachments
came in rapid succession to round out the universal use of this
camera. Most of these accessories are carefully described in the
various chapters to which they relate. However a few of the impor-
tant accessories not illustrated elsewhere in this book are shown in
this chapter.

Vidom Universal View Finder

As the direct optical view finder in the Leica is only used for
the 50mm lenses it is necessary to use the Vidom Universal View
Finder for all other interchangeable Leica lenses. This finder con-
tains an adjustable diaphragm which is easily moved by turning a
calibrated ring to include the field of view of any Leica lens. The
diaphragm is rectangular and the sides retain the standard 2 to 3
proportion of the Leica negative size when changed for any field of
view. Thus if the Vidom Finder is used with a 90mm lens the
calibrated ring is turned to the figure 9 (opposite the long line) and
the adjustable diaphragm will then include the exact field of view
between 30 feet and infinity. "When taking close-up pictures between

Fig. 26 Vidom Universal View
Finder Used for Determining Field
of View of the Various Leica
Lenses.

to 6 feet set the figure representing the focal length of the lens
opposite the short line on the finder. For distances between 6 and 30
feet set the figure between the two index lines.

A parallax adjusting lever is located at the rear base of the Vidom
Finder with calibrations of 3^, 5, 7, 15 feet, and °° or infinity. As
the finder is attached to the top of the Leica and not directly behind
the lens this parallax adjusting lever is used to make the proper
inclination of the finder in order to include the exact field covered
by the lens. Thus this finder is used by many Leica owners for taking
close-up photos with the 5Qmm lenses. The direct view finder already
attached to the Leica does not have this parallax adjusting feature.

The eyepiece of the Vidom Finder rotates in a 90 degree arc in order to
keep the image right side up when using the camera in the horizontal or
vertical positions. When using this finder to photograph rapidly moving
objects it is best to keep both eyes open in order to make it easier to keep
the object in the center of the finder.

Another valuable use of the Universal Finder is in determining the
field of view in pictorial photography without the camera. By sighting
through the finder one can easily determine if there is a picture worth taking
without the necessity of removing the camera from the case. Such a con-
venience is of special value when working with the longer focal length
lenses.

Wide Angle View Finder

Although the Universal View Finder includes the field of the 35mm
wide angle lens there are times when the smaller wide angle direct view
finder is used. This wide angle finder is about the same size as the 50nim
finder on the Leica, with the exception that it covers the 35mm lens field.
Leica users will find this Wide Angle Finder very useful when the 35mm
lens is to be used a great deal, because the camera and additional view
finder can easily be slipped into a pocket when not in use.

Rasuk Direct Vision View Finder

A non-optical direct view finder, known as the Rasuk, is recommended
for certain types of sport, newspaper, theatre, and general pictures. This

finder consists of a rotating metal masking frame
and a peep sight for centering the images. A
removable reducing mask is used with the 105mm
and 135mm lenses. When this mask is removed
the frames cover the fields of view included in the
35mm, 50mm, 73mm, and 90mm lenses.

Fig. 27 Direct Vision Frame
Finder Attached to Leica.

The rear peep sight has a small rectangular opening for use with all
lenses except the 105mm and the 135mm lenses. A small round peep sight
is moved into position for using the Rasuk Finder with these 105mm and
135mm lenses.

Leica Equipment

The rear sighting frame can be slightly raised or lowered for obtain-
ing the proper parallax adjustments. There are three engraved marks of
3%, 7, and oo (infinity). For close-up pictures between 3% and 7 feet
the parallax adjustment is quite necessary in order to include the exact
field of view. Leica users who wear glasses may find this finder of spe-
cial value as it may be a little easier to follow the objects and properly
frame the picture. With a little practice both eyes may be left open
when the Easuk Finder is in use. This is of particular value when fol-
lowing a fast moving object. With both eyes open the object may be seen
very quickly before it comes into the field of view for photographing, and
thus the final picture will be taken with the object in the correct position.

Fig. 28 Adjustable Fig. 29 Regular

Lens Shade. Lens Shade. Fig. 30 Wintu Angle View Finder.

The Wintu Angle View Finder

We are all familiar with the way in which most pictures are taken by
pointing the camera directly towards the subject with the operator also
facing in the same direction. By using the Wintu Angle View Finder the
conventional picture taking methods are abandoned with the Leica held at
a right angle to the direction in which the operator is facing. In other
words, you can take the picture around a corner and not attract attention
or have the people, to be included in the picture, assume unnatural poses
or expressions. This finder is also of particular value for making candid
camera pictures.

To mount the Angle View Finder on the Leica it is only necessary to
slip the metal bracket into the clip on top of the Leica, then move the
small angle prism over the range finder eye-piece. By sighting through
the small angle prism the object can be quickly focused when using the
Model D or F Leica with the built-in range finder. After focus is secured
shift the eye to the eye-piece of the Angle View Finder.

There is also an Angle View Finder (Winko), without the angle prism,
for use with the Leica Models A, C, and E. With a little practice an
Angle View Finder will be of great value to the traveler, candid camera
worker, and the general photographer.

Sunshades and Their Use

Whenever possible it is advisable to use a sunshade or lens hood on
the Leica lenses. Such protection eliminates any possibility of stray light
from entering the lens and thus causing a slight halation on the film.
This fact is true of any photographic lens, and the larger the aperture
the more important it is to use a lens shade to cut off the strong side lights
which have no photographic value.

There are numerous lens shades available for the Leica camera.
Leitz produces a small metal sunshade for the 35mm and 50mm lenses.
An adjustable shade is made for the longer focal length lenses, with the
exception of the 73mm and 105mm lenses which are already supplied with
their own shades. This adjustable shade has engraved markings for each
focal length, and the proper setting is quickly made.

Correction Lenses for

Range Finder and View Finder

Persons who wear eyeglasses find it difficult at times to focus with the
aid of the range finder or to see the entire field in the view finder, because
the eyeglasses prevent them from placing their eyes close to the camera.
This difficulty can be overcome by the use of special Correction Lenses on
the eye lenses of both the range finder and view finder.

The Correction Lenses embody the same correction as that contained
in the eyeglasses worn by the Leica user. When these special lenses are
placed both on the view finder and the range finder, it is not necessary to
wear eyeglasses and the eye can be placed close to the camera. The Leitz
Co. has in stock the necessary Correction Lenses to correct nearsightedness
and far-sightedness (myopia and hyperopia). It is but necessary to obtain
the prescription of one's eyeglasses from the optician or optometrist and
the proper Correction Lenses will be supplied. These screw into the eye
lenses of both the range finder and the view finder.

Special lenses to correct astigmatism are also obtainable. However,
it is necessary to secure them on special order. In this case the prescrip-
tion for the eyeglasses must also be furnished.

When to Use the Wire Cable Release

When making either time or instantaneous exposure the Wire Shutter
Release is of special value. For example, this release is indispensa-
ble for making exposures in photomicrography, all types of close-up copy
work, and wherever exposures are to be made where it is essential not to
jar the camera. The Wire Release is screwed over the release button of
the Leica after the metal protective bushing has been unscrewed.

When it is advisable to operate the Leica at a distance of 10 or 20
feet the longer corresponding wire releases are recommended. For exam-
ple, the 20 foot release may be used to release the Leica shutter after the
camera has been set to photograph a bird or possibly when the photogra-
pher wishes to be included in the picture.

Slow Timing Device

Owners of the Leica Models A, C, E, and D may adapt their cameras
to the slower shutter speeds between l/20th and 1 second by using the
Slow Timing Device. As it is cheaper to secure one of these attachments
than to have these earlier Leica models converted to the Model F, there
is a definite advantage in using one of these Slow Timers.

This Slow Timing Device is screwed directly to the release button of
the Leica. To operate: wind the shutter of the Leica and set the shutter
speed dial to Z the same as for a time exposure. Next, set the Slow
Timer by turning the two knobs of the Timer clockwise until the dial comes
to a stop. To set for the proper speed lift the longer part of the metal
band slightly and turn back or forth until the index line at its outer edge
points toward the speed required.

Leica Equipment

The shutter is released by pressing the release button, located on the
side of the Timer, either with the finger or a Wire Release. Press the
release down slowly and hold the finger there until the shutter lias opened
and closed, in order to avoid shaking the camera during the short moment
when the shutter is open.

On some of the older cameras the release button varies slightly in
height, thus it may be necessary to make a slight adjustment on the Slow
Timer before it will operate correctly. To make this adjustment simply
use a screw driver and turn the large screw head, located in the hollow
shaft of the Timer, to the right or left until the proper release is secured
If the release button of the camera is too low the adjusting screw of the
Slow Timer may not have sufficient pressure upon the shutter release
button... in this case the screw is turned anti-clockwise. If the button
is too high, the rotating levers in the attachment do not work properly,
consequently the shutter opens only half way and remains open. In
such a case the adjusting screw is turned clockwise. Once the proper
adjustment has been made for your camera the Tinier will need no addi-
tional change.

Rapid Winder

There are many occasions when the Leica user may wish to take
successive pictures within a very short period of time in order to record
continuous actions. The Rapid Winder has been made to serve this pur-
pose. With this attachment extremely interesting picture series may be
made of dancers, animals at play or running, children, wrestlers, and
rapidly moving objects of all kinds.

The Leica Rapid Winder replaces the base plate of the Leica camera.
A trigger is pulled after each exposure is made. This trigger action
causes the film to be wound and the shutter set at the same moment.
With Leica Cameras from serial No. 1, up to and including No. 111,449, the
small pin which holds on the base plate must be changed to a larger pin
to accommodate the Rapid Winder which also necessitates a new base plate,
A new winding spindle and winding knob must also be supplied as these
cameras are not equipped with a notched winding shaft. Cameras num-
bering from 111,449 up to and including 159,000 must be supplied with a
new winding shaft and knob for the shaft. A special Rapid Winder for
use on all Leica cameras with serial numbers below 159,000 is available in
case the camera is not to be changed.

Fig. 32 New type Rapid Winder
with trigger action which fits over
base of Leica.

Protective Cases for Leica Equipment

All Leica equipment should be kept in protective cases when not in
use. Such protection will keep your equipment looking better and also
prevent the camera or lenses from receiving scratches or hard knocks.

Sand and dust will be kept out. Too much emphasis cannot be laid upon
the importance of keeping all Leica equipment neatly fitted in their
proper cases.

There are Eveready cases for the camera only. Soft leather cases
for the Camera only and for individual lenses. Then there are a number
of combination cases available for the camera, additional lenses, and other
extra equipment such as filters, view finders, and extra film magazines.
All color filters should likewise be kept in soft leather cases or the orig-
inal filter box to prevent scratching and the collection of dirt on the glass
surface.

Optical Short Distance
Focusing Device "Nooky"

This new and ingenious attachment extends the usefulness of
the automatic focusing principle of the Leica beyond its present
range. Heretofore the shortest distance for which the setting of
the lens could be secured automatically was 3y2 feet. By Linscrew-
ing the lens from the camera and screwing the "Nooky" into its
place, and subsequently attaching the lens by its lugs to it, sharp
focus can be instantly secured on all objects from approximately
40 inches to within 18 inches of the camera.

The ""Nooky" attachment can be used on models D, F, FF
and G Leiea Cameras. It is intended for use with 50mm lenses and
as this issue go-es to press, it is available for the Elmar 50mm lens.
Later it will become available in models for other 50mm lenses.

In using this device outdoors, as for details of plants, flowers
and insects, one should focus quite critically and take care that in
shifting the eye from the range-finder to the view-finder the camera
should not be moved out of focus. "When you are only 18 inches
away from your object the movement of an inch forward or back-
ward makes a difference. Outdoors as well as indoors stop down
as much as you are able to take in the fullest depth possible, and
allow for any error in focusing.
A framing mask is incorpor-
ated into the optical range finder
part of this device which ingeni-
ously and automatically compen-
sates for the shift of the field due
to parallax.

At the short distances for
which this attachment is intended

Fig. 34 Optical Short Dis-
tance Focusing Device
"Nooky"

Leica Equipment

"Small Print" Manuel Komroff

Elmar 50mm with "Nooky" 2 sec. f :12.5 Panatomic film—Harvey Developer.

the depth of focus is obviously very small. It is extremely im-
portant in focusing the lens to employ only the center of the field
measured through the range finder when the double edge of the
framing mask enters the field of vision. Unless very short expos-
ures are called for due to inadequate illumination it is important
to stop down the aperture of the lens to at least f :4.5 to increase
its depth of focus. The following table gives the approximate
depth of focus at the various settings of the lenses and at various
distances as well as approximate size of the field covered at the
various distances:

DISTANCE: DEPTH OF FOCUS AT LENS STOPS: APPROXIMATE

Object to lens
Inches

39%
35%
31%'
27%
23%
19%
17%

f: 3.5 4.5 6.3 9

12.5 18 FIELD COVERED:

12%

18%

16%

CICJ

les

24%

31!

•6%

13%

14%

21%

3%-

10%

12%

19%

1.%

.1%

.3%

10%

16 14

5%'

13%

I1!

7i4

10%

Above figures are rounded off to nearest

Single Exposure Leiccx

Eecently the Single Exposure Leica was introduced to meet the demand
for making single negatives instead of the strip of exposures on the ordi-
nary roll^of Leica films. This camera consists of a small housing which is
the exact depth, from lens flange to film surface, as the regular Leica
camera models. A removable ground glass plate, film holder, and one
of the Leica lenses completes the outfit. Some of the advantages and uses
of this camera may be mentioned as follows:

1. Used as a lens tester. The distance between lens flange and ground
glass is 28.8mm which is exactly the same as the distance between the
lens flange and film surface in the regular Leica models. The exact
field of view of the various lenses can be quickly checked by focusing the
images upon the ground glass of the single Exposure Camera.

Fig. 35 Single Exposure
Leica. Note Film Holder,
View Finder and Shutter.

2. For use in photomicrography. Single micro pictures can be quickly
made with this camera and* developed in a small tray either for testing
exposure, filters, or for making permanent records. Use this camera
without a lens but with a 6cm extension tube between the Single Ex-
posure Leica and the eyepiece of the microscope, with a black cloth
around the tube to exclude stray light. The camera is mounted on a
rigid support beside the microscope. Such an arrangement makes a
very inexpensive photomicrographic outfit, and insures perfect results.

3. As a copying camera. Any type of copy work can be done with this
Single Exposure Leica by using an adjustable mounting and the vari-
ous extension tubes or the front lenses. If desired, it is possible to
obtain various fixed distances with the lens which can later be shifted
to the regular Leica for making pictures on the longer strip of film.

4. For making portraits. It is quite easy to compose portraits on the
ground glass of this camera before changing to the film holder and
making the exposure. The 1.2cm extension tube can be used for close
ups when necessary. If one of the 50mm lenses is used the collapsible
feature of the lens barrel can be adapted to obtaining proper focus.

5. Also for general photography where only one picture is to be made
at a time, especially where it is necessary to test exposures, color filt-
ers, and films before using the regular Leica camera.

To set up and operate the Single Exposure Leica proceed as follows:

1. Attach the camera to a tripod, Sliding Arm on the copy attachment,
or any other rigid support.

2. Screw in one of the interchangeable Leica lenses and fit the Ibsor
46

Lelca Equipment

shutter over the front of any lens except the 73mm which has a diam-
eter larger than the others. If the Ibsor shutter does not fit tightly,
simply press down the cut flange until a tight fit is secured over
the lens.

3. Attach the wire cable release. Usually there is a small pin which
comes attached to the shutter; this is used for making exposures by
setting the shutter and inserting the pin into the small hole on the
face of the shutter, and then removing the finger from the shutter
setting lever. The shutter remains closed, but the moment the pin
is withdrawn the shutter will open and close at the proper speed setting.
A string can be attached to the pin so that the operator can easily
get into his own picture after pulling out the stop pin and making the
exposure.

4. Next see that the ground glass is clipped into position with the ground
side of the glass facing toward the lens. Then secure the proper focus
by moving the lens mount around and watching the image on the ground
glass.

5. When exact focus has been secured replace the ground glass with the
single film holder. Pull out the dark slide covering the film. Make
certain that the shutter is not open over the lens while withdrawing
the slide. Then make the exposure, replace the slide, and remove the
film holder.

When preparing the single cut films for this camera it is a good idea
to wind the 35mm film in an opposite direction, with the emulsion side out,
and left that way for a few hours or several days before using. After this
treatment it will be found that the filra lies much flatter and it is easier
to cut into single exposure lengths. It is also advisable to cut all the film
required at one time and keep the pieces between single black papers in a
light-tight box or envelope until used.

Use the width of the dark slide as a guide for cutting each individual
film. The width of this slide is the exact length of the film for one single
exposure in this camera.

Devei0pment of these single films can be carried out in a small tray.

Summary

Many other accessories for the Leica camera will be described
in the following chapters. There are also many circulars giving
directions and booklets available from the Leitz Company on the
various Leica attachments. Directions are supplied with every
accessory when purchased. Therefore the greatest emphasis in this
book has been laid upon the actual use of these accessories. The
reader is invited to carefully study all of the following chapters,
even though he may be interested in only one or two subjects. By
reading about the way in which the Leica is applied to other uses, it
is possible to pick up many suggestions which can be applied to one's
own particular field of Leica photography. Also by reading these
various chapters you will obtain a more complete idea about the
scope of the Leica and thus be able to understand and offer sugges-
tions to your Leica associates who may be working in these more or
less specialized fields of photography.

Manuel Komroff
48

Harold Harvey

LENSES

EL W. ZIELER CHAPTER 2

"What kind of a gadget is this? Is it a movie ?"

"No, it is a little camera. Did you ever hear of the Leica?"

"Oh yes — so, this is a Leica; it certainly is a compact little
thing! How large a picture can you take with it?"

"The pictures are not much larger than a postage stamp; but
you can enlarge them to almost unbelievable sizes. ' ?

' ' Gee whiz — it must have a marvelous lens ! ' '

Why does everybody think at once of the lens when he sees a
miniature camera? Why must a small camera have a particularly
good lens? What properties characterize a good lens? What does
the lens have to accomplish and how well does it succeed? How can
you use your lens equipment to best advantage and why may you
want to have several lenses?

When miniature photography was in its infancy, there were
many sceptics who pointed out that an enlargement can never be
as sharp as a contact print; and since the small negative must always
be enlarged considerably, the loss of detail, it seemed, ought to be
so great that the enlargement would be of little value.

Practice soon gave ample proof to the contrary. But practice
alone is often considered as insufficient proof because you may have
to use all kinds of tricks which only the expert knows. To set our
mind at ease about the possibilities of miniature cameras we may
start our investigation about lenses by finding out, how sharp the
negatives of miniature cameras are. It is true that an enlargement
must always be less sharp than the original negative because the
same detail is stretched over a larger area. Still it is quite possible
that we may not be able to detect any difference.

Suppose we have before us two pages covered with printed mat-
ter. Some clever printer may have been able to make the letters
on one page as small as l/500th of an inch. But the second page may
have letters as small as l/1000th of an inch. We hold these two
pages as far away from the eye as we would hold a moderately sized
photograph. Of course, we would not be able to read these pages.

We would not even be able to see from this distance which of the
two pages has the smaller letters.

The capacity of the human eye to make detail distinguishable
or, the resolving power of the human eye, is limited. If we com-
pare two objects as, for instance, a contact print and an enlarge-
ment, the former having detail ten times smaller than the resolving
power of the eye and the latter having detail which is only three
times smaller than this limit, we may not be able to detect any dif-
ference in sharpness.

The limit of resolving power of the human eye has been deter-
mined by experiment and calculation. It is customary to express
it by the magnitude of the smallest detail In the object which cai
still be resolved. This magnitude depends, of course, upon the dis-
tance from which we view this object. If we want to see finer de-
tail, we move the object closer to the eye. But the angle of vision
under which the finest resolvable detail appears, always remains the
same. Thus it has been found that, allowing for slight variation oJ
individual power of vision, the limit of resolving power of the human
eye is about 2 to 3 minutes of arc. That means that in an objed
held about ten inches from the eye we cannot see detail if it is closei
together than l/100th part of an inch. If the object is 20 inches
from the eye, the detail must be 2/100ths of an inch apart if we are
to distinguish it.

Now we have to investigate how closely the detail can be crowdec
together in a negative from a miniature camera. This investigation
is rather involved and it is to our advantage if we penetrate more
deeply into the entire process of the formation of images by lenses

Let us select the simplest object possible : one luminous point
Figure 38 shows a diagram of a simple experiment. A lentil-shapec
piece of glass is placed at a certain distance from the luminous point P

A sector of light of the angular aperture a passes through thi
glass and in doing so it changes its original direction. Each Hgfr
ray is broken or, in scientific language : refracted. The more obliquely
the rays meet the surface of the glass, the more pronounced is the
change in direction. By skillfully shaping the piece of glass we maj
be able to guide each ray in such a manner that, after leaving the
lens, the entire btgndle of rays converges as a cone of the angulai
aperture b until the rays meet again in one single point Pa, which is
the image of the original point P.* This is the essential principle oJ

* If we hold a screen in the plane I-I we see on it one bright spot
50

Lenses

the formation of a real image. When photographing a complex ob-
ject the lens collects diverging bundles of rays from each object point
and must unite them in image points which must have such location
in respect to each other that they reproduce the object in the image
plane.

Fig. 38 Formation of a Real Image of a Luminous Point

It is the job of the lens designer to skillfully shape the lens. In
practice this job is so immensely difficult that we may say, it is im-
possible to succeed completely. In the first place it is next to impos-
sible to grind and polish accurately enough any surfaces of unusual
shape. In fact, in photographic lenses we only find lenses with
spherical or plane surfaces. But even if we were not limited in this
respect, we would meet with many other difficulties. These light rays
are tricky individuals. One single ray of white light, for instance,
upon entering the lens, begins to disintegrate into rays of various
colors and finally a rainbow colored cone of light leaves the lens.
This phenomenon is known as chromatical aberration. We also must
contend with the fact that if we use spherical lenses, the outsiders,
the rays which meet the lens with greatest obliquity, are bent too
strongly and refuse to come to the same meeting point where the
rays of the center of the cone unite. This is known as spherical
aberration.

There are many more misbehaviors of light rays which give the
lens designer a headache. If he wants to guide these rays to the
same point he cannot restrict himself to the use of one single lens.
He must combine several pieces of glass, selecting different materials
and shapes and placing them at accurately determined distances
from each other. Thus he creates a photographic objective of the
type shown in figure 39 which is the famous Elmar lens of the Leica
camera.

You will see the definite plan of construction: a single plano-
convex lens is followed by a biconcave lens, placed at a definite dis-

tance from the first. Behind this second element there is a pair of
lenses cemented together. Each lens has spherical or plane surfaces
which in a diagram appear as parts of circles or straight lines. The
centers of all these circles lie on one straight line, called the optical
axis.

Fig. 39 Cross-section of
Elmar 50mm f :3.5 Lens

the

Fig. 40 Cross-section
of the Hektor 73mni
f :1.9 Lens

There are other types of objectives* such as the Hektor shown in
figure 40, the Summar and many others. Each of them is bnilt
according to a different plan and represents an effort to make the
rays behave, but no effort is completely successful. There is always
a sacrifice in some respect, as we shall see later.

With one of these objectives we may perform a few interesting
experiments. Of course, we cannot actually select as an object one
single luminous point. But we may produce a disc of light of a
definite and small diameter. Suppose a ground glass is placed before
a bright lamp and again before the ground glass an iris diaphragm
which can be contracted to very small diameters. Thus we may pro-
duce a luminous disc of, say l/10th of an inch. We place the lens
at a certain distance from the light source and on the other side of it
we place a screen so that on it the image of the luminous disc appears

* "At this place, I wish to emphasize that I prefer the word 'objective'
to the word 'lens', although the latter term is more popular. A lens is really
one piece of glass whereas an objective is a compound unit and consists of
several lenses."

Lenses

with, maximum sharpness. The conditions may have been so selected
that the image has a diameter of l/200th of an inch. In other words,
the image is twenty times smaller than the object. Now we reduce
the opening of the iris diaphragm to l/30th of an inch and the image,
again twenty times smaller, is l/600th of an inch. But as we further
reduce the diameter of the luminous disc (perhaps to l/100th) we
find that the image retains the size of l/600th inch.

This is a very important discovery. Suppose we would have
two luminous object points, each of them very small, for instance
1/lOOOth of an inch in diameter, but less than l/30th of an inch apart.
The lens, when forming the image at the same ratio of reduction as
before, (20:1) reduces the distance between the images to less than
l/600th but at the same time each of the images occupies l/600th.
The two image discs overlap, melting so to speak into each other. We
have now overstepped the limit of resolving power of the lens.

This experiment reveals a very important fact regarding the
performance of optical instruments : the image of a theoretical object
point is never a point but a light disc of definite, measureable
diameter. But if we think that the actual magnitude of this disc can
be made smaller and smaller as manufacturing methods and the art
of lens designing improves, we are greatly mistaken. Unfortunately
there are definite limits which cannot be overstepped and they have
their cause in the very nature of light itself.

In a diagram we may indicate a light ray by one straight line, but in
reality we find that as light progresses with infinite speed in the direction
of this line, very minute vibrations take place with enormous frequency.
Physicists have attempted to explain the many strange phenomena which
light can produce, by assuming that it propagates like a wave motion.
To help our imagination we may make a comparison. Suppose that you
throw a stone into a lake. From the center, where the stone hits the
surface of the water, we see a wave motion spreading with equal speed in
every direction as circles of ever increasing diameter. From crest to crest
of successive waves there is always the same distance, called the wave
length. This wave length may be small or large. The motion of the
waves probably spreads with a speed of several feet or yards a second.
But as these waves move away from the center, the surface of the water
only moves up and down so that if a piece of wood is swimming on the
water, it is carried up and down but not away from the center of the dis-
turbance.

If light proceeds from a luminous point, waves of unbelievably small
wave length spread with equal speed in every direction. This speed, how-
ever, is very great, almost 200,000 miles per second. The vibrations take
place at right angles to the direction of propagation. And, to come back
to the formation of the image of a point, where the light is concentrated
into the image point, we find an enormous confusion of vibrations from
light waves of different lengths and directions. These waves partly inter-
fere with and cancel each other but still they spread the light over a

certain area. In fact, if we would study this area through a microscope,
we would find a small disc of light surrounded by rings of light of very-
weak and rapidly diminishing intensity. This is called a diffraction pattern.

We need not penetrate further into these theoretical optical matters.
We must only realize that even a theoretically perfect objective has a lim-
ited resolving power. This theoretical resolving power depends mainly upon
the angle of convergence of the cone of light which the lens concentrates (in
fig. 38 this cone is marked 6). The larger this angle, the smaller is the finest
detail which a theoretically perfect objective could reveal.

But here we can see the difference between theory and practice. It
is unfortunate but true that, as we try to make objectives with great light
concentrating power, the difficulties which we encounter increase beyond
description. These misbehaviors of light: spherical and chromatical aber-
ration and many others, can hardly be held in check. If we are content
with a small cone of light, the situation can be controlled quite nicely. A
small cone, of course, contains so to speak, only a small amount of light
and when photographing we would have to give very long exposures. In
this age of speed this would be a serious handicap. Therefore there is a
constant race between the manufacturers to produce lenses of greater light
concentrating power: but the task before them is very difficult indeed.
The Iris Diaphragm and the Resolving Power

As you know, photographic lenses are equipped with iris dia-
phragms with which the angular aperture of the cone of light, and
therefore also the light intensity in the plane of the image, can be
regulated. As we open or close this diaphragm the difference be-
tween theory and practice evidences itself as follows:

a. "When the iris diaphragm is closed, the difference between theory
and practice is least noticeable. At the same time the theoretical
resolving power is at its worst.

b. As the iris diaphragm is gradually opened, the practical insuffi-
ciencies come more and more into the foreground. This does not
mean that any practically produeeable lens yields the sharpest
images when the iris diaphragm is closed. In fact, in a good lens
the sharpness will increase as we begin to open the iris. Only,
it will not increase as much as can be theoretically expected.

c. If the iris diaphragm is opened considerably, the misbehaviors of
light finally become so noticeable that even the actual sharpness
decreases.

A good method to judge the quality of a lens is, therefore, to find
out how much the iris can be opened with a beneficial effect upon the
sharpness, the resolving power, of the lens.

Every photographer should realize the full significance of this
fact and should not believe the wrong statement that any lens per-
forms best when the iris is closed as, far as possible.

But let us not forget our original question: How sharp is a
miniature negative? The actual limit of the resolving power is not

Lenses

the only factor to consider. We must not forget that the image which
the lens has formed is recorded on the film, which is coated with a
light-sensitive emulsion. The emulsion is turbid and has a certain
thickness. As the light penetrates into the emulsion, it is scattered
and the record of the image of one single luminous point upon the
film emulsion will necessarily occupy a larger area. Thus the film
emulsion introduces a certain loss of sharpness. If we wish to find
a quantitative measure for the sharpness of a minature negative we
must measure the diameter of the image disc on the emulsion when
the object is so small that its image is equal to the limit of resolving
power of the lens. This area is often referred to as the circle of con-
fusion, because within this circle there is a great confusion of aber-
rations, diffractions, dispersions and many other misbehaviors of light.

Thus it has been found that the diameter of the circle of con-
fusion of the better lenses, such as are used in miniature cameras,
does not exceed l/800th of an inch, even when the diaphragm is open
and the practical discrepancies are most apparent. Upon closing the
iris diaphragm, the sharpness improves, then retains this optimum
value until finally, as the aperture assumes very small values, it de-
creases slightly.

"We learned in the beginning that the smallest detail which the
human eye can detect from a distance of 10 inches is about l/100th
of an inch. If the detail in a miniature negative is crowded into as
small a spot as l/800th it is quite evident that this negative can be
enlarged 8 times without noticeable loss of sharpness.

If you really want to look at the picture you will never hold an
enlargement of 8 x 10 inches closer than 10 inches from the eye. Only
grain fiends have a habit of smelling their pictures, regardless of
size. We, who want to enjoy the pictures which we have taken, have
learned that an enlargement may appear as sharp as a contact print
and thus we may confidently discard bulky equipment in favor of the
small and compact Leica. Its existence is built upon a sound scientific
basis and, as far as sharpness of the picture is concerned, we may
safely say that for our purposes it is sufficiently equivalent to the
large camera.

The Miniature vs Larger Cameras

With this fact established we shall now proceed to find that in
other respects the minature camera is definitely and considerably
superior to the large camera. Above all, it has reconciled two oppos-
ing factors which cannot be mastered with larger cameras : speed of
the lens and depth of focus in the negative.

You will often have found in photographs that some parts of the
picture were sharper than others. Either the objects close to the
camera are sharp and those further away appear fuzzy; or the back-
ground is sharp and the foreground is out of focus; or there is a
range-in-between which is imaged crisply, whereas the very near and
very far objects lack in sharpness. The photographer can, at will,
select the range of object distances within which everything is imaged
with the best possible sharpness and, if he uses his camera correctly,
he can always direct the attention of the spectator to the subject of
interest. There is, then, a range within which everything is equally
sharp and this range represents the depth of focus.

In photographs of general outdoor scenes and many other types of
pictures it is highly desirable, if not essential, that the entire picture be
in perfect focus. Only in portraits and group pictures it often is of spe-
cial advantage to reproduce in sharpest focus only the subject of interest
and to have foreground and background intentionally out of focus, in order
not to distract the attention of the spectator.

If you compare Leica snapshots with those of a larger camera, you
will notice at once the increased depth of focus in the Leica enlargement.
I used the word snapshots for a special reason because as long as the big-
camera owner is allowed to increase the time of exposure of his photos as
much as he wants, he can also produce pictures of remarkable depth of
focus. He must only close the iris diaphragm.

On the mount of a photographic lens a whole series of numbers is en-
graved which, upon first sight, seem to have no sensible relation to each
other. But if in a competition between large and small camera the iris
diaphragm is in both cases set to the same figure, for instance f :4.5, and
then the two pictures are compared in regard to depth of focus you will
win the race by a wide margin if you were the one who used the miniature
camera. And if you had inquired from your competitor about the time
of exposure of his picture, you would have found out that it was the same
as that which you gave, provided you both gave the correct time.

In other words, the iris diaphragm affects not only the depth of focus
but also the time of exposure. It seems important to study both functions.
We begin, of course, with the effect upon the depth of focus. But even
before we comedo this, we must explain why the large camera, when the
iris diaphragm was set to the same figure, yielded images of less depth
of focus.

Depth of Focus and Relative Aperture

We resort again to experiments. "We take a lens for a 5 x 7 inch
camera and the Elmar 50mm lens. In both eases we set the iris to
the figure f :4.5 although we do not know as yet what that means. We
also need two screens, on which to project the images and a yardstick
ruled in very fine units, with which we want to measure, not only the
distance between screen and lens, but also the size of the images on the
screens.

-5^^i£^^i^^^?I^SBwRrJ

»^S^W9*;«p;SK,aiPii!

Fig. 41 Fields Covered by Six Different Leica Lenses. All Photographs
Made From the Same Point

Since we want to explore various ranges of object distance, we
select at first an object which is very very far away: the sun. We
move the screens back and forth behind the lenses until the images
are as sharp as possible. "We see in both cases a very small and very
brilliant spot. The screen for the large lens is about 10 inches behind
the larger lens, whereas the other one is about 2 inches behind the
Blmar lens.

This distance at which the image of an infinitely distant object
is formed, is called focal length of the lens* If we have held the
lenses so that their optical axes pointed directly into the sun, the
images are formed in the focal points. The screens are in the focal
planes of the respective lenses.

The focal length of a lens is a very important factor. It deter-
mines the location and size of the images which the lens forms
of objects at different distances, the depth of focus, the perspective
and many other things and is one of the main keys to the secret of the
performance of the lens.

A comparison of the sizes of the images which in our experiment
both lenses have formed of the sun reveals that, although both of thenj
are very small, yet the one formed by the Elmar is still the smaller
one.

From the experiment we learn that the image of an infinitely far
object is formed in the focal plane and that the lens with the smaller
focal length forms the smaller image.

Now let us select another object which is nearer, for instance a,
telegraph pole which is about 30 feet high and 100 feet away. We
discover that the screens must be moved farther away from the lens
in order to be in the plane of the image. When the screens are prop-
erly focused the one of the 10 inch lens is 0.084th of an inch
(or 2.12mm) behind the focal plane. Had we left it in the focal
plane, the image would have been anything but sharp. The size of
the image of the pole, incidentally, is about 3 inches high.

The screen of the Blmar lens, however, had to be moved only
0.0033th of an inch (or 0.085mm). This is not much more than the
thickness of a sheet of paper. Therefore it is not surprising that even
as long as this screen was left in the focal plane, the image was still
remarkably sharp. As to the size of the image of the pole, which the
Elmar has formed, it is only 5/8th of an inch high.

* Actually the focal length is the distance of the focal point from the
so-called principal plane. Readers interested in optics may find further
Information in physics textbooks.

JLenses

This experiment will convince you that the Elmar lens of the
Leiea camera forms images of greater depth of focus. The image of
the sun (many millions of miles away) was practically in the same
plane as that of the telegraph pole which was only 100 feet from the
lens. But now remember figure 38 where the rays coming from one
object point converge to a small spot and then diverge. As you move
the screen farther away from the lens, the rays from this object point
occupy a larger and larger area. At the same time the cone of rays
from a nearer object point would still be in the process of converging.
You must also remember that the image which a lens forms of a point
even in the plane of maximum sharpness is never a true point but a
small disc (circle of confusion). Thus we can illustrate the entire
situation in a diagram shown in figure 42.

Fig. 42 Depth of Focus "with Iris Diaphragm Open

Fig. 43 Depth of Focus with Iris Diaphragm Closed
Point P is imaged at P3 where the image occupies a circle of confu-
sion of the diameter A — B. Point Pw nearer to the lens, is imaged
farther away so that in the plane I— I the rays are still as far apart

as A B. The geometrically correct plane of the image of point P!

is farther away, at P4.

On the other hand, point P2, farther away from the lens than
P is imaged closer than P3 and in the plane I-I .the rays have diverged
so much that they occupy the area A — B. The total effect is that
on the film held in the plane I — I the images of all three points are
equally sharp and as sharp as the limit of resolving power of the
lens.

If you have understood this relation, you will be able to answer
the question: what happens when the iris diaphragm is closed fur-
ther? The angular aperture of the image-forming cones of rays
becomes smaller and the rays converge and diverge less rapidly. Thus
the depth of focus increases. This is shown in the diagram of
figure 43.

To summarize: Lenses of shorter focal length have greater depth of
focus. The depth of focus of a lens of given focal length increases when
you close the iris diaphragm.

Depth of Focus Scale

As mentioned before we find on the lens mount a scale with, numbers,
the meaning of which we have not yet explored. All we know is that these
numbers refer to different apertures of the iris. But at the base of the
lens mount, there is a beveled ring on which from one center index mark
to both sides we find the same numbers as on the iris scale. These numbers,
in connection with the distance scale on the lens ring enable you to read
the depth of focus for each aperture of the iris.

You can close the iris to the mark f :4.5, focus the lens to an object
which is 20 feet away and the depth-of-focus scale informs you that now
even objects as close as 14% and as far as 32 feet are in perfect focus.

If you make intelligent use of this depth-of-focus scale, you can greatly
enhance the quality of your pictures. It is not always advisable to have the
greatest depth of focus possible. In a portrait, for instance fine effects can
be obtained by intentionally reducing- the depth of focus, so that everything
except the features of the subject is out of focus. Thus the attention of the
spectator is at once directed to the subject of interest.

Even in other cases you can make good use of the scale. If on your
honeymoon you want to take a picture of your bride at Niagara Falls you
might be equally interested in showing the beauty of the falls. If you set
the iris to f :9 and your bride is 15 feet from the camera which is correctly
focused for this distance, everything from 9*/£ to 35 feet is in focus but the
falls which are farther away, are not sharp. But if you consult the depth-
of-focus scale you may learn that with the iris at the same stop, the same
distance from the camera to the bride but the focusing mount set to a dis-
tance of 27 feet everything from 12% feet to infinity is sharp. You have
sacrificed the foreground for the benefit of the background. Many photog-
raphers do not realize the full significance of this possibility to correctly
"place" the range of depth of focus.

At this place it is advisable to draw attention to the fact that the
depth-of-focus scale should not be taken too literally. You must realize
that the smaller the circle of confusion, — or to express it differently, the
sharper the image or the better the correction of the lens, — the smaller is
the range of depth of focus for a given aperture. The scales are mostly
based on an assumed size of this circle of confusion which is still small
enough to permit enlargements to about 8 x 10 inches. It was mentioned
before that upon closing the iris, the actual resolving power increases.
Quite a number of other factors,, such as the thickness of the emulsion on
the film, etc., have to be considered. Therefore, the actual range of maxi-
mum sharpness (especially at smaller aperture of the iris) is not identical
with the depth of focus indicated on the scale although even within this
latter range, the sharpness is still satisfactory.

Lexises

If on the other hand your best friend wants to get your goat by boast-
ing that his lens of the same focal length and the same aperture has a
greater depth of focus, don't be jealous, just pity him because either he lies
or he admits with his boast that his lens is not as well corrected as yours.

Thus we conclude our investigation regarding the depth of focus
and direct our attention to the other function of the iris diaphragm:
The regulation of the amount of light which passes through the lens.

Exposure Variations

It is quite easy to comprehend that if we close the iris diaphragm,
less light passes through the lens. But this knowledge alone is of
little help to us. Suppose we had to close the iris to one-half of its
original aperture in order to have enough depth of focus in the pic-
ture; how much, do we have to increase the exposure? Bather than
try until we hit by accident the right time of exposure, let us analyse
the situation. Figure 44 helps us in our investigation.

Fig. 44 Principle of "Relative Aperture"

m
IT

Four rays, marked I to IV come from a distant point. If the iris
diaphragm is fully open, the entire amount of light between the rays
I and IV is collected by the objective. But the diagram shows only
a cross section of the lens. Actually these rays would fill an area
represented by the circle No. 1 at the left side of the diagram.

If we close the iris diaphragm to one-half of its original diameter
only light within the cone of the rays II to III filling the area of the
circle No. 2 would be able to pass through the lens. Although this
circle has one-half the diameter of that of No. 1, you will remember
that the area decreases with the square of this ratio. Thus only one-
quarter of the original amount of light passes through the lens when
the iris diaphragm is closed to one-half. Closing it further to l/3rd
of its original aperture would, of course, reduce the intensity to
l/9th, etc.

Bealizing this we could make a scale which carries the number
1 when the iris is fully open, number 4 when the iris is closed one-
half; number 9 when it is closed to l/3rd, etc. These numbers would
indicate the increase in exposure necessary when the iris is partly
closed. But this would not fully solve our problem. Suppose you
want to compare your Elmar with the lens of your old-fashioned
competitor with the 5 x7 camera. His lens has a much larger diam-
eter. Does it collect more light when the iris diaphragm is fully
open? Comparative exposure data may show that even with the iris
so far open that the actual diameter of the cone of light entering
his lens is twice that of your lens, he requires longer exposures.
What we need is an absolute system so that we can compare the light
transmitting power of lenses of different focal lengths.

Do not forget that the lens of the 5x7 inch camera, having a
focal length of 10 inches, also forms relatively larger images. If for
instance a lens of different focal length has twice the diameter of
your Elmar but objects at identical distances are imaged twice as
large, the greater amount of light passing through the larger lens is
also spread over a larger area (this area too increasing with the
square of the size of the image) so that the actual intensity in each
point of the image is the same as that in the image of your Elmar.
Both lenses have the same light transmitting capacity.

In other words, the actual diameter of the lens is no useable
measure for the amount of light collected by it. "We must compare
it with the focal length of the lens which, as you know, also deter-
mines the size of the images. The ratio : focal length divided by the
effective diameter of the lens has therefore been introduced as the
standard measure for the light collecting power of the lens. The
increase in exposure when closing the iris diaphragm can always fae
found by comparing the squares of these ratios.

A practical example will illustrate how you must proceed : The
lowest figure on the aperture scale of the Elmar lens is f :3.5. Since
the focal length of this lens is 50mm, the actual effective diameter of
the lens is 50:3.5 (or 14.3mm). How much longer do you have to
make the exposure if you close the iris diaphragm to f :4.5 ? Divide
the square of 4.5 (or 20.25) by the square of 3.5 (or 12.25) and
you will find that with the smaller aperture you must expose 1.67
times as long. If in the first case (Ms at f :3.5) you had to give an
exposure of 1 second, you must expose 1.67 seconds with the iris at
f .4.5 in order to obtain a negative of the same density.

But if you have once established the correct exposure for certain
light conditions and a definite relative aperture of the lens (for in-

Lenses

stance f :4.5) you can give this exposure to any photo, regardless of
the focal length of the lens. The Hektor 135mm at f :4.5, the Elmar
90mm at f :4.5, the Summar 50mm at 4.5, the Elmar 35mm at f :4.5;
all these lenses at these apertures require the same time of exposure.
Stick to this rule, even if supersensitive experts tell you that they
have discovered minute variations in densities of negatives thus taken.
The latitude of the film will protect you.

Also remember that the effective diameter of a lens, even when
the iris diaphragm is fully open, is not equivalent to the diameter of
the first element in the lens but to the diameter of the cone of rays
in an optical reference plane called entrance pupil. The size and
shape of the first element depends entirely upon the plan of design
of the lens and can vary even if the light transmitting power re-
mains constant.

Perspective and the Various Leica Lenses

Before we discuss the merits of the various objectives for the
Leica camera, a few words must be added in regard to the perspective
in a photograph because the focal lengths of these lenses vary from
28mm to 200mm and sometimes you may be in doubt whether you
should go close and use a short focus lens or take a lens of longer
focal length and go farther away from the object until you see the
same relation between image and frame size in the field of the view
finder.

We have seen that the focal length of the objective determines the size
of the image of any object at different distances. It is to our advantage
if we become acquainted with the exact mathematical relation between the
focal length, the object distance, the size of the object and that of the image.
This relation can be expressed by the following1 equation :

JO __ D — f
I"" f

the symbols finding their interpretations as follows:

0 = size of the object

1 = size of the image

D = Distance of the object from the lens
f = focal length of the lens.

This fundamental equation should remain in the memory of every pho-
tographer because he can derive great benefit from it. The left side repre-
sents the ratio of reduction in the image. Here is how you can apply it:^

Suppose you have obtained permission to photograph the animals in
the zoo. There is a beautiful lion which you wish to photograph. The bars
of the cage are about 15 feet from where the lion generally reposes. Which
objective should you take along so that you can hold the camera between the
bars of the cage and snap the picture without wasting space on the negative
for the empty cage?

The lion is 6 feet long (72 inches) and the longer side of the negative
is 1% inch. The ratio of reduction must be 72 : 1% or 48 : 1. The object
distance is 15 feet (180 inches) . The equation tells you that the objective
which you should use must have a focal length of 3.6 inches or about 90mm.

But we can gain more valuable information from this equation. You
know that objects which are far away appear small and those which are
close appear large in the picture. This accounts for the perspective in the
picture.

The ratio at which the image size decreases with increasing object
distance likewise depends upon the focal length of the lens and can easily
be determined with this equation.

Suppose you want to photograph the telegraph poles along the road
side. They are about 20 feet high. The first pole is about 75 feet from
where you stand and the distance between each following pole is 75 feet.
At first you take a photograph with the 90mm lens. The equation tells us
that the image of the first pole is 24mm high, that of the second pole is only
12mm high or one half the size of the first one.

Now you change to the Elmar 50mm, but you remain standing where
you were. On this negative the first pole appears as an image of only 13mm
and the second' one is about G^mm. Although both images are smaller the
second pole appears again at one-half the size of the first one. From this
experiment we learn that: lenses of different focal lengths, used for photo-
graphing from the same distance show identical perspective in the image
but different ratios of reduction. The smaller the focal length the greater
the ratio of reduction.

But when you use the 50mm Elmar you can go closer to the first
pole until its image is again 24mm high. You must now approach it until
you are only 41.7 feet away. But now the image of the second pole is only
8.6mm high or only slightly more than l/3rd of the size of the first one.
From this experiment we learn that: lenses of different focal lengths used
for photographing so that the ratio of reduction of the image of one given
object remains the same, show different perspective. Lenses of shorter focal
length yield images with more pronounced perspective.

If you hold side by side the two photographs of the telegraph
poles taken with the 90mm Elmar and th^ 50mm Elmar from differ-
ent points of view so that the first pole in both cases is equally long
in the pictures, you may want to know which of the two has more
natural perspective. The general problem involved is somewhat com-
plicated because various factors are involved. For instance, we must
give consideration to the size of the enlargement and the distance
from which we look at it. But in general we may assume that an
enlargement of 5 x 7 inches is held about 10 to 12 inches from the eye
and as the size of the enlargement increases we also increase the dis-
tance from which we view it.

Under these conditions the most favorable focal length of a
lens for the negative size of the Leica camera is 50mm. A lens of
this focal length will yield images of the most natural perspective.
It is, therefore not surprising that this is the focal length of the
most popular Leica lenses.

Lenses

Only if you want to photograph from a rather close distance, as
in portrait photography, it is advisable to select a lens of slightly
longer focal length. As we come too close to the subject, the size of
the image increases so rapidly that there is a tendency for the image
of the closest features to be unproportionally larger than that of the
farther features. Then you obtain pictures where the nose is large
and the ears are too small. Such portraits are not nattering. Some
photographers are of the erroneous opinion that for portrait photog-
raphy the miniature camera is altogether unuseable. This assumption
is wrong. In fact, the miniature camera can produce portraits with
a perspective which is identical to that which we find in portraits
taken with cameras of larger negative size. A lens of about 73 to
90mm will do the trick. The reader who is sufficiently interested in
this problem will find a detailed investigation by the writer in the
October 1934 issue of Photo Art Monthly. If we select an objective
of still longer focal length, the portrait will even lack in "plasticity"
and the faces will appear too flat.

We have gradually acquired knowledge about some of the most
fundamental principles of photographic lenses in general and can
appreciate the special requirements of lenses suitable for miniature

Fig. 45 Indian Guides

Elmar 90mm Lens, Panatomic Film

Felix Schoedsack
65

cameras. The family of Leica lenses has grown steadily and we may
summarize our knowledge by discussing each of them.

The Hektor 28mm f:6.3. This lens has the shortest focal length of
all available for the Leica camera; as such it yields pictures having the
greatest depth of focus. Even with its diaphragm wide open at f :6.3 when
fixed at infinity the range of sharpness of this lens will include everything
from infinity to within as little as 12 feet from the camera. Incidentally,
the short focal length of this lens accounts for the great reduction in size
of the image of objects that are apparently near the camera. This .power
of reduction permits us to cover a much larger field and to crowd more
things into a single frame of the Leica negative. The lens actually collects
rays within an angle of 76° into the frame of the negative. It is distinctly
a wide angle lens. The perspective which is quite accentuated off ers attrac-
tive possibilities to the skillful photographer especially on account of its
almost unlimited depth of focus. These two factors: rapidly receding per-
spective and depth of focus are very useful in the treatment of architectural
subjects. The "super speed" photographer may consider this lens slow
because its largest opening is only f :6.3. One should realize, however,
that for a specifically wide angle lens having such extremely short focal
length, yielding images so completely free from distortion — the aperture
of f :6.3 may be considered an achievement of 'optical craftsmanship. The
lens comes in a non-collapsible mount, its short focal length making it
possible. A special view finder which renders a clear and brilliant image
of the field is available for this lens.

The Hektor 28mm Wide-Angle

Lens with its Special Brilliant

View Finder.

The Elmar 35mm f:3.5. This is another member of the wide angle
lens family which covers an angle of view of 65°. While the angle of
vision is somewhat smaller than that of the Hektor 28mm, this is amply
compensated by greater light collecting power of its comparatively large
aperture of f :3.5. Pictures made with this lens have considerable depth
of focus and their perspective is more nearly approaching that of normal
vision. These two features of the Elmar 35mm lens make it an ideal
medium for snapshooting. Set for infinity, with its diaphragm slightly
stopped down it requires almost no focusing. From the depth of focus
scale we know that with the diaphragm set for f :6.3, when the lens is
focused for 30 feet, the range of sharpness will extend from 10 feet to
infinity. Thus focused, the camera can be kept in constant readiness in
the pocket or in the Everready case. Due to its short focal length the lens
does not need a collapsible mount and protrudes only slightly beyond the
body of the camera, rendering it very handy for quick work. Though
its field of view is adequately covered by the Vidom Universal View Finder
so many people find it more convenient and expedient to use in connection
with this lens the special small view finder available for it. It fits snugly
into the clip of the camera upon the range finder, combining maximum
convenience with minimum of bulk. For general outdoor photography the

Lenses

speed of f:6.3 is quite adequate. If candid photographs have to be made
in artificial light, when critical focusing- may require more time than is
available — the lens can be left wide open and set to an approximate focus.
The aperture of f :3.5 is often sufficient to secure usable negatives even in
artificial illumination if super-sensitive film is used.

Fig. 46 Elmar 35mm
f:3.5 Lens with its
Special View Finder
which fits into the
camera clip.

The 50 mm Lenses

The Elmar 50mm f :3.5. This is the lens which made the Leica camera
famous. The sharpness of the pictures taken with this lens was responsible
for the immense success of the Leica. It may be remembered that more
than 35,000 Leica cameras were sold before a model with interchangeable
lenses was offered. The Elmar 50mm is still the best standard lens upon
which you can build' your equipment. This lens really set a new standard for
the correction of the optical equipment of cameras and carries a great share
of the credit for having put across the idea of miniature photography. The
Elmar plan of design was later on used for four other Leica lenses of 35mm,
90mm and 105 mm.

The maximum sharpness in the negative prevails when the objective
is stopped down to about f:6.3 or f:9; and upon closing the iris further
there is no noticeable decrease of sharpness in the negative.

The depth of focus of this Elmar 50mm is still remarkable and it was
with this lens that the surprising possibilities of miniature cameras in
combining speed of the lens, depth of focus and sharpness of the negative
were first demonstrated so successfully to the public who became at once
enthused about miniature photography. The perspective of its pictures is
natural. The lens can even be used for portrait photography although in
cases where extreme close-ups are taken, it should not be used, unless you
make use of a simple trick. Place the subject somewhat farther away and
when you make the enlargement, use only 2/3rds of the center portion of
the negative.

Fig. 47 Elmar
50mm f :3.5 Lens

Fig. 48 Hektor
50mm f:2.5 Lens

In summarizing the merits of this Elmar 5iOmm one point should not
be forgotten: the price question. Before the Leica appeared, an objective
of an aperture of f :4.5 for a large camera was considered extremely fast,
because faster lenses were hardly obtainable. Faster lenses were not made
because their price would have been so prohibitive, that there would not have
been any market for them. Only when the Leica with its objectives of
short focal length made its debut, faster lenses became accessible for the
amateur.

The Hektor 50mm f:2.5

This lens differs from the Elmar of the same focal length in two
respects: in the first place, the name implies that it is built upon a different
plan of design and secondly it has a higher speed. It was the thirst of
the amateur for still more speed which was to be satisfied with this new
type lens and this higher speed necessitated a new plan of construction.
The difficulty before the lens designer was great indeed. The cry for more
speed did not indicate whether the amateur knew how much more expensive
a good lens of this type would have to be. The step from f :3.5 to f :2.5
means an increase of speed of 100%. You may know that if the top speed
of a car would have to be doubled, it would become necessary to design a
new model which may be three to four times as expensive. Such margin
was not available for the lens designer. The speed increase would have to
be gained by making a sacrifice in some other respect. If we follow the
historical course of events we must not forget that when the Hektor 50mm
was created an enlargement of 5 x 7 inches was considered rather a satis-
factory size. Strange, how quickly fashions change! From the short skirt
to the long skirt was hardly more than a year. From the 5x7 enlargement
to the monstrous size of 16 x 20 from a Leica negative was only a few
years !

But the Hektor 50mm with 100% increase in speed and a slight de-
crease in sharpness at full aperture, was so designed that even if the iris
was closed only to f :4.5 or f :6.3 the sharpness equalled if not surpassed
that of the pictures of the Elmar 50mm. And furthermore, this lens has
one other slight advantage over the Elmar. Its plan of design made a
slightly higher color correction possible. Critical and impartial amateurs
may have noticed slightly superior results with the Hektor 50mm over those
of an Elmar 50mm when using panchromatic films.

In spite of these advantages and a moderate price the Hektor 50mm
lost some of its popularity as soon as a faster lens became available,
although at a still higher price.

The Summar 50 mm F:2

This lens must be considered as a triumph of the science of optics.
You will remember that the quality of a lens can be judged by finding
how much the iris diaphragm can be opened with beneficial increase
in sharpness of the picture. When we come to as high an aperture
as f :2 we may be satisfiedby seeing how little the sharpness decreases.
The Summar 50mm at this high aperture yields images so sharp that
even when enlarged to the size of 8 x 10 inches the smallest detail is
still beyond the limit of resolving power of the human eye if the photo
is held 10 inches from the eye.

Lenses

With the iris diaphragm fully open the speed of the Summar
50mm is three times as high as that of the Elmar at its best. This
speed is enough to enable the photographer to take photos even under
extremely unfavorable light conditions. Thus it was with this fast
lens that the Leiea camera conquered another field : candid and stage
photography. And as the miniature camera is used for more and more
seemingly impossible tasks, these fast lenses also opened the field of
snapshooting with infra-red sensitive films and filters. These invisible
rays to which film emulsions can be made sensitive, are so different
from the rest, that it is not surprising that they refuse to unite with
the visible rays in forming an image, even if they pass through as
excellently corrected a lens system as the Summar 50mm.

But the focusing scale of the Summar provides for a correction
so that if you have eliminated the other rays by means of a filter,
you can still obtain sharp pictures with infra-red rays. On this scale
you will find two index marks, one of which is provided with a letter
R. Suppose you have focused the camera on an object and the
regular index mark points to 30 feet. Before you take the photo,
simply turn the focusing mount slightly until the mark with the
letter E points to the distance of 30 feet. Then you will obtain a
sharp picture.

Fig. 49 Summar 50mm
f:2 Lens in Collapsible
Mount

The Xenon 50mm f :1.5
Superspeed Lens.

The Xenon 50mm, f:1.5. As this edition goes to press we
learn of the fulfillment of the dream of so many Leica fans. A
lens of the ultra sp-eed of f :1.5 of the standard focal length of
50mm has become available. This addition to the family of the
Leica lenses is so recent that only this last minute announcement
of it can be made in this edition. First photographs made with
this lens reveal a remarkable over-all sharpness throughout the

entire negative area up to the very- edge and corner of it. This is
an outstanding accomplishment for a lens of such high light trans-
mitting power. Two such photographs made under ordinary light
conditions with the lens wide open are being offered to prove the
claim. The lens is finished in beautiful and durable chromium and
its mount is so designed that its rotation for critical focusing can
be accomplished either by moving the regular locking thumb-knob
or by grasping the outer knurled collar of its mount. Some people
find that the latter method assures smoother operation. This lens
should gratify the yearning for high-speed lenses of even the most
radical speed fiends for some time to come.

Eddie Cantor by J. Winton Lemen Oakland Bridge Anton F. Baumann

Xenon 50mm, f:1.5, 1/100 sec. Hektor 28mm, f:12.5, 1/40, Panatomic,

the Hektor 73 mm F:1.9

This lens has a slightly noticeable softness at full aperture. But
this trace of lack of sharpness is very much less pronounced than
that in its cousin of 50mm focal length. Such improvement could be
accomplished because in the plan of design of the 73mm lens it was
preferred to place perfection of correction before the necessity of
a low price.

Lenses

The lens is perhaps the best among- those offered for the Leica
for the purpose of portrait photography and here this minute effect
of softness is rather a benefit. In portrait photography the smaller
range of depth of focus which results from the longer focal lengtli
and higher speed is also an advantage because the subject of interest
can thus stand out more distinctly against the blurred background.

With the diaphragm closed to f :4.5 or more, the sharpness of the
pictures obtained with the Hektor 73mm also surpasses that of the
pictures taken with the Elmar 50mm, especially when panchromatic
film is used.

Fig. 50 Hektor 73mm f :1.9 Lens Fig. 51 Elmar 90mm f :4 Lens

The Elmar 90 mm F:4

The general characteristics of this lens need hardly be enumer
ated because they are evident from the preceding general' remarks. In
regard to sharpness it fulfills every expectation. The depth of f oeus
is naturally smaller than that of the Elmar 50mm. But in outdoor
photography the lens will mostly be used for longer distances and
then the depth of focus is sufficient for all purposes. Its speed is
high considering the rather long focal length. It is also an ideal
objective for portrait work.

Due to its price, which is lower than that of the Hektor 73mm,
the Elmar 90mm may also deserve preferred consideration in com-
pleting a lens equipment. 'With three lenses, of 35mm, 50mm, and
90mm focal length, almost any task can be fulfilled.

The Thambor 90mm f:2.2

Undoubtedly this lens will contribute considerably towards a successful
invasion of the field of Portrait Photography with the Leica camera and
will convince those who still have serious objections to portrait photo graphy
wi£h this small camera. Its focal length is ideal for portrait photography
and its extremely high speed offers three distinct advantages. In the first

place, it permits a reduction of the depth of focus which is often necessary
in portrait photography when we wish to have the subject stand out against
a soft or unsharp background. Secondly, this high speed of the lens permits
shorter exposures or less light, so that even under unfavorable light condi-
tions it may be possible to take snapshots. This is an important point if we
aim for natural and unposed expressions of the subject and wish to avoid
the somewhat self-conscious and lifeless artificial effects which are so often
found in posed portraits.

Finally, the high relative aperture and the very peculiar and entirely
novel plan of design of this lens make it possible to obtain a soft1 focus
effect which can be varied within wide limits. The means which are avail-
able for this purpose are somewhat unusual and quite ingenious. Since
aside from the well known means of increasing the sharpness of soft
focus lenses by closing the iris diaphragm (thus reducing the amount of
spherical aberration which the marginal rays cause, and which produce
the soft focus effect) there is also the possibility of eliminating the rays
in the center by introducing a so-called "center spot".

This "Center Spot" is introduced over the
front of the lens by means of a disc of opti-
cally flat thin glass in a screw-in mount which
has a small semi-opaque spot in its center,
which "closes" the center of the lens to all
light. This method of obtaining a soft focus
creates very pleasing effects in portrait pho-
tography as well as general photography with
back light.

When this lens is "stopped down" further,
the image will be really crisp and sharp so that
the Thambar can also be used for regular land-
scape photography and other purposes. These

TTV co mi mi u ™ f eatures and the agreeable fact that the Tham-

Fig. 52 The Thambar 90mm , . , . , , . , , . , .

f:2.2 Lens with its "Center bar 1S relatively low priced (considering its

Spot" Disc in a Screw-in very high relative aperture) make it a useful

Mount and versatile Leica lens.

The Elmar 105 mm F:6.3

In many ways similar to the 90mm lens, this Elmar may be pre-
ferred by the tourist who wishes to economize in weight of equipment
and needs the longer focal length for photography at long distance.
The lower speed is not directly objectionable because when you take
a picture from the peak of a mountain to the next you usually have
ample light at your disposal. (As this edition goes to press we learn
that the production of this lens is being discontinued.)

Lenses

The Hektor 135mm f:4.5

This is decidedly a lens for long distance photography. Although
still useable for portrait work, the critical judge may notice a certain
flatness (lack of third dimension) in portraits taken with the Hektor
135mm.

These lenses of long focal length are sometimes called Teleob-
jectives. The expression is misleading, to say the least. The term
actually refers to a type of long focus objectives with a very definite
plan of design, consisting of a combination of a convex lens system.
As you will remember, the Hektor type has improved color correc-
tion and at apertures not exceeding f :4.5 it yields images of per-
fect sharpness. Those who use panchromatic or infra-red sensitive
film with red or infra-red filters may find the Hektor 135mm the
best lens for long distance photography.

Fig. 53 Hektor 135mm f :4.5 Lens

The Telyt 200mm (8 in.) f:4.5

This new lens is a Tele-Objective in the full sense of the term
(a true TELEPHOTO lens). It is so designed that the distance
between the film plane and the lens is shorter than the focal length,
a feature which is characteristic of the Tele System on which this
lens is based. This is obtained by introducing a negative lens element
back of the positive lens element. Thus, while the focal length of
the Telyt is 65mm longer than that of the 135mm lens its barrel is
only 3.3mm longer. It will be remembered that the Hektor 135mm
lens is not built on the principle of the Tele System but is a regular
anastigmat of long focus. The Telyt is the first Tele System objec-
tive in the series of Leica lenses. Its correction is excellent so that
it produces images entirely free from distortion. Particular atten-
tion'was given to chromatic correction which makes the lens available
for long distance photography with panchromatic and Infra-Red
film in connection with red and Infra-E-ed filters. Excellent results
may be expected in this type of work. It should be remembered,
however, that for long distance photography clear atmospheric con-
ditions are quite essential. While aerial haze can be overcome with

the aid of haze-cutting filters, it is almost hopeless to attempt to
photograph across so-called ''heat-waves" or heat currents caused
by rapidly rising layers of air heated by sunrays or by heat reflected
from the ground. Such conditions cause local variations of the
refracting power of the air, resulting not only in decreased sharpness
of the photographic image but frequently in its complete distortion.

The long focal length of this lens made it possible (and neces-
sary) to equip it with a special mirror reflex focusing device con-
tained in a small and compact dice-like box which is attached directly
to the camera. For this particular lens such a method of focusing
was preferred to the direct coupling to .the automatic range-finder.
It combines the advantages of extremely accurate focusing with the
convenience of viewing the entire picture on the ground glass of the
mirror reflex box through a 5x or a 30x magnifier.

Best results can be obtained with the Telyt only if a good tripod
is used or if the camera and lens are otherwise rigidly supported.

The Telyt, as compared with the standard 50mm lens, yields
a magnification of 4x. Its view angle is approximately 12°. Its
focusing mount permits direct focusing by scale from infinity to

Fig. 54 New Telyt 200mm f : 4.5
Telephoto Lens. Shown Com-
plete With Reflex Housing 5x
Magnifier and Synchronized Re-
leases

Lenses

Two Photographs Taken
From the Same Position
with the 28mm Wide
Angle and the Telyt Lenses

Fig. 55 Photograph Made
with the 200mm Telyt
Lens

Fig. 56 General Wide Angle View Obtained with the Hektor 28mm Lens

9 feet. At 9 feet it covers an area of approximately 12 x 18 inches.
Special extension tubes are available for this lens permitting close-
ups down to a working distance of 4 feet from the camera, at which
distance the lens will cover an area of 4 x 6 inches, yielding a
magnification on the negative of approximately 4^x.

The basic principle of interchangeability of Leica lenses has
been maintained in the Telyt. The mirror reflex housing can also
be used with other Leica lenses, particularly with the Hektor 135mm,
which can be supplied in a special shortened mount (without the
automatic coupling), which is simply screwed into the reflex housing
in place of the Telyt. When thus used the lens is acting as a normal
135mm objective and can be used up to infinity.

Using the Mirror Reflex with Other Leica Lenses

Other Leica lenses of shorter focal lengths are limited to close-
ups when used in connection with the reflex housing. If the focusing
mount of the respective lenses is set for infinity the resulting ratio
of reduction or magnification respectively (on the film) is as follows:

Lens: Focal Length Ratio of reduction (on film)

(lens set for infinity)

Hektor 135mm 1:2.2

Elmar 105mm 1:1.7

Elmar

Thambar > 90mm 1:1J5

Hektor 73mm 1:1.2

Ratio of magnification (on film)

(lens set for infinity)
Elmar

50mm 1.2:1

Summar

Xenon

Elmar 35mm 1.8:1

Hektor 28mm 2.2:1

For estimating correct exposure with these lenses, whose focal lengths
are reduced by their use in connection with the reflex housing, formulas
offered in the chapter on copying and close-up photography should be con-
sulted. The length, of the reflex housing (considered as an extension
tube) is 62mm.
Front Lenses and Close Distance Photography

The problem, of photographing objects at close range can be
solved in two different ways: either we can introduce intermediate
extension tubes to increase the distance from the lens to the plane of
the negative, or we can reduce the focal length of the lens system by
placing front lenses before the regular objective.

The use of extension tubes directly on the camera together with table of working
distances, ratio of magnification etc. will be found on page 195.

Lenses

As we see from the Front Lens tables, these auxiliary optical
systems permit the photographing of objects with the Leica camera
from 31/2 feet to 10 11/16 inches from the camera back. The smallest
object which can thus be photographed to fill the negative frame
measures 3%x5 inches. If we wish to compare the optical principle
of photography with Front Lenses and with intermediate rings, we
must again recall a few optical principles. It will be evident that
if in figure 58 the object point would have been infinitely far away,
a practically parallel bundle of rays would have entered the lens.
We have neglected so far to mention that if the lens is so designed
that it will converge with the highest perfection any parallel bundle
of rays, it is by no means to be understood that this same lens system
will converge with the same perfection (although in another plane)
a divergent bundle of rays from an object point which is nearer to
the lens. In other words, a lens which will yield the sharpest image
without spherical aberration when the object is far away will not
yield as crisp an image when the object is close to the lens. As the
object moves from infinity to minimum distance of 3^ ^eet the
amount of divergence of the bundles of rays entering the lens is quite
negligible, but if the object comes considerably closer the spherical
aberration would become so noticeable that the images would suffer
considerably in quality.

If we add a Front Lens to the Leica objective, we reduce the
focal length of the entire lens system in a peculiar way and we learn
from the tables that for instance through the addition of Front Lens
No. 1 to the Elmar 50mm we can set the focusing mount to infinity
when the object is only 39% inches away. The Front Lens converts
the slightly divergent rays into a parallel bundle so that through
this addition the Elmar, in order to photograph an object at 39^
inches, yields an image of the same quality as one photographed at
infinity without the Front Lens. This same principle is consistently
applied so that with the Leica focused to 31/2 feet, we can photograph
objects at an actual distance of 22 9/16 inches when we add Front
Lens No. 1. The front lens tables give further details.

What we have to cope with particularly when photographing at short
distance is the misbehavior of light which is called "spherical aberration".
We will recall that the marginal rays have a tendency to converge closer
to the lens than the rays passing through the center of the objective. The
marginal rays can always be eliminated by closing the iris diaphragm.
Since in close-up photography, every optimum of detail rendition is abso-
lutely essential, we cannot afford to leave the diaphragm wide open but
have to close it to such an extent that through compromise of the small
remaining defects in a lens system which have been described before, the

actual sharpness of the image is most favorable. The front lens tables con-
tain definite information how much the Leica lenses have to be stopped down
for the Front Lenses and various distances.

Supplementary Front Lens Elmar lens
Fig-. 58 Path of Rays in the Elmar Lens with Supplementary Front Lens

Another interesting fact relates to the f values of the regular Leica
lenses. As long as we use Front Lenses for close-up photography, original
f values retain their value because the actual light intensity gathered by
the objective and expressed by the so-called f value is represented by
the figure: distance from lens to image divided by the diameter of the
lens. Since the use of a front lens enables us to use the same focusing
mount at close distance we find that for photography of an object at 39%
inches with front lens No. 1 the distance from the lens to the film is the
same as if we would photograph an object at infinity without the front
lens. It is therefore possible to measure the actual intensity of the object
with a standard exposure meter and compute the value for the respective
aperture of the lens at which we take the photograph.

These hints may be valuable for those who use the Front Lenses
and it may be added that these auxiliary optical devices' are par-
ticularly advantageous if we wish to obtain the crispest sharpness
and best detail rendition in flat objects within the range of distances
indicated in the Front Lens tables. The question of photography
at still closer distances is covered in Chapters 9, 17, 18, 20, and 21.

Proper Care of Lenses

It seems advisable to conclude with some suggestions relative to
the care of the miniature camera lenses. All lenses are made with an
accuracy which can hardly be found in any other piece of manu-
factured goods. The lens surfaces must be so smooth and so accu-
rately spherical that even a deviation of l/100,000th of an inch
would affect their performance. It is quite evident that such a delicate
and accurate piece of equipment requires special care and can easily
be ruined by careless handling.

The first rule for the care of lenses is therefore: keep the lens
surfaces free from dust and other impurities. When the lens is at-
tached to the camera and not in use, see to it that it is covered with
the lens cap. When the objective is removed from the camera, use
the dust cap to close the other side so that the lens surfaces are not
exposed and no dust can collect on them.

Lenses

Should the surfaces show deposits of dust or other impurities,
do not try to remove it by rubbing the surface with your fingers.
You may wipe the surfaces with a piece of silk cloth or with a piece
of lens paper. You can also use a fine camel-hair brush. In any
case it is imperative that the surface be wiped very gently. The
dust in the air is full of little abrasive particles which could scratch-
the surface of the lens. The smallest scratch is in comparison to
the length of a light wave like a deep and wide trench since a light
wave is as small as l/50,000th inch. You may secure a small bottle
of xylol and a package of lens paper and always moisten the paper
in the xylol when cleaning the lens surfaces. In wiping the lens,
have the paper make a circular motion.

If a lens surface is once scratched, it is not possible to simply
repolish this surface beca,use such action would make the entire lens
thinner and would affect the optical performance. Only a replace-
ment of this lens can fully repair the damage.

Under no circumstances should the photographer try to take the
lens apart. Such warning may seem unnecessary to many miniature
camera owners, yet it is given in view of experiences which have
repeated themselves only too frequently. A photographer may try to
insert a color filter between the lens elements, may try to clean the
inside surface or find another excuse for satisfying his curiosity and
take the lens apart. He will be sadly disappointed when he finds out
how hard it is to reassemble the lens so that no dust remains inside.
The lenses are assembled by the manufacturer in rooms which are
absolutely free from dust and special instruments are used to keep
dust from the insides of the lens.

Sometimes lenses show a few very minute bubbles in the glass.
These are not objectionable. The area of one bubble in comparison
to that of the entire lens surface, is very small and whatever small
amount of light is thrown off its course by this bubble is by far too
minute to cause any photographically recordable light impression. A
long scratch over the lens surface is much more serious.

Altogether the photographer in trying to repair a lens should re-
strict his activity to a minimum. As long as the objective is kept
closed by lens and dust cap no danger of serious trouble will ever
arise. If something irregular comes into evidence, the objective
should rather be sent to the manufacturer.

Sahuaro James M. Leonard

Elmar 35mm, l/100th second at f :12.5, No. 1 Filter, Du Pont Superior Film

HENRY M. LESTER

KARL A. BARLEBEN, Jr. CHAPTER 3

A filter is a medium which, allows light rays of a certain kind to
pass through, while it is more or less impervious to others. From its
very definition, it appears that its function is purely subtractive ; it
adds nothing in the way of illumination ; it merely eliminates from
light certain qualities which may be undesirable. This is the reason
for the increase of exposure generally required when filters are used.
Thus a filter should be looked upon as just another means of con-
trolling light and illumination in addition to the others at our dis-
posal. These are the shutter — for control of length of time during
which the light is permitted to reach the film; the lens diaphragm —
for control of quantity and optical quality; the filter — for control of
color quality or intensity. Additional means of light control are
available in the form of reflectors and diffusers.

Photographic color filters are usually made of glass. The coloring
which renders it capable of absorbing certain colors of light, while
allowing others to pass freely, is imparted to it by several methods.
Certain dyes are mixed with the glass in its molten state, thus render-
ing it colored before polishing and shaping. This provides the most
satisfactory type of filter for use directly on the camera lens, it being
thin, uniform, color-stable, and unaffected by changes of temperature
and climatic conditions. Only breakage or scratches on the surface
will impair its usefulness.

Color filters are also prepared by coating gelatin containing a
given quantity of an organic dye upon optically flat and otherwise
prepared glass, and after drying, stripping this film from the glass.
The film is then cut to any size or shape and mounted between two
pieces of optically flat glass by means of a special cement (Canada
balsam) under heat and pressure. This type of filter requires greater
care in handling than the solid glass type. Improper handling, contact
with water, alcohol or high temperatures will render it useless.
Humidity or exposure to direct action of sunlight also causes deteriora-

tion. This type of filter should never be selected for use in the tropics
or for sea travel. However, for use in a temperate climate, with care-
ful handling, it will prove entirely satisfactory. Gelatin filters are
available in a far greater number of colors than solid glass filters, and
being less expensive, are to be recommended for special purposes and
experimental work.

Still another type of filter is obtainable in the form of a so-called
water cell, which consists of a glass container having two parallel
sides filled with distilled water into which the dye required is dis-
solved. This type of filter is used especially in scientific work, such as
photomicrography, where it acts not only as a color filter, but also as
a heat absorption filter. It is placed, not between the lens and the
photographed subject, but between the latter and the light source.

For the purpose of general Leica photography, we are concerned
only with the first two types of filters, either of which may readily be
slipped on and off the lens of the camera. Of these two, the solid glass
type filter is much the better for the Leica camera on account of port-
ability. Gelatin filters have a definite place in the kit of the experi-
mentally-minded worker, or one whose specialized work calls for an
endless variety of filters for tests and for other specific purposes.

Solid glass filters are to be preferred not only because of greater
stability and permanence, but also because of simplicity. Any medium
transmitting light affects its course to a greater or lesser degree,
depending upon whether it is optically flat. If it is, the disturbance
is negligible. s The greater the number of media the light has to
traverse, the greater the disturbance of its course. Thus, when light
penetrates thin solid glass, it is affected only by the process of enter-
ing it on one side, traversing its dyed mass and emerging on the other
side. Pure gelatin filters used without mounting between glass would
be just as effective were it possible to handle them in such form. But
a gelatin filter, cemented between two pieces of glass, requires the
light to pass through glass, Canada balsam, gelatin, Canada balsam
and* glass again. Obviously it is simpler to produce a filter with two
piano-parallel (optically flat) surfaces than one possessing ten sur-
faces meeting this requirement. Of course, this is merely a theo-
retical, rather than a practical, objection, but it is frequently con-
firmed in practice resulting in pictures of lesser sharpness and poorer
definition.

As a matter of fact, it should be known that filters actually affect
the sharpness of the picture, the type of the filter merely accounting

Filters

Fig. 61 Summer Solitude John L. Davenport

Elmar 50mm, 1/100 second at f :4.5. Filter: 23A, Du Pont Superior Film

for the degree of unsharpness. Theoretically speaking, the shorter
the wave-length of light, the sharper the image. Violet and blue
light, having the shorter wavelengths, are capable of producing
sharper images. If a dense filter is used which holds back the entire
amount of blue light, it permits only that light which has the longer
wave length to reach the film, with the resulting decrease in sharp-
ness of the image. Moreover, some lenses are not so well corrected
for light of the longer wave length so that they cannot yield relatively
as sharp an image as that obtainable in the presence of blue rays.
In other words, the use of filters results in pictures of lesser sharpness
because the very element which contributes most to sharp images
has been eliminated or weakened.

What has been said about filters and their effect upon sharpness
of images should not be taken too literally. For practical purposes,
the effect of a good filter upon the sharpness of the image is, as a
matter of fact, quite negligible. Most of the objections are of a
theoretical nature based upon careful and painstaking comparisons
made under the microscope. The purpose of these objections is not
so much to discourage the use of filters as to produce a more in-

their products which gradually make the use of filters less essential.

When Faters Should Be Used

Filters can and should be used if their choice and application
are made judiciously and not indiscriminately. They are intended to
establish and correct contrasts between various degrees of brightness
in the picture. The human eye has the ability to distinguish, not
only between light and dark, but also between colors. Colors pro-
duce the sensation of various degrees of brightness. Since color
cannot be rendered through black and white photography, we make
it reproduce our sensations of the varying degrees of brightness in
terms of black, white and intermediate shades of gray. To com-
pensate for the inability of the film to interpret things in terms of
telligent and judicious attitude towards their application in Leica
photography. Our nearest photographic relatives, the cameramen of
Hollywood, using almost the same negative material, employ filters
extensively. But their results tend only to confirm what has been
said: their knowledge of emulsions, plus their knowledge of filters,
yield results of rare excellence and quality.

It may not be amiss to qualify filters as the " necessary evil" of
miniature photography. They are something to be used if absolutely
necessary, but it would be better, whenever possible, to do without
them.

Undoubtedly, this very feeling prevailing among photographers
causes manufacturers of film to strive for those characteristics in
degrees of brightness as does the eye, we use filters. It is important
to realize that ordinarily we would need no filters if the film repro-
duced colors at the same scale of tonal values as the eye sees them.
This is important because film manufacturers strive to approach this
millenium, and modern film materials require the use of filters to a
much lesser degree than the older types of film.

Basically, color filters, as used in photography, can serve a two-
fold purpose: to establish the balance of color values, or to upset
that balance. When the contrast between the various degrees of
brightness in the pictures approximates that perceived by the eye —
the balance is considered established. Depending upon the emulsion
used, it is then normal or corrected, When the contrast between the
various degrees of brightness is rendered differently from the
visual perception — it is said that the color values, interpreted in
terms of shades of gray, are undercorrected or overcorrected. A
black sky or a dark gray sky with white clouds in a midsummer
landscape is an example of overcorrection, while a white sky with

Filters

light gray clouds in a similar picture would indicate under correction.
An intentional upsetting of the balance of color values may lead to
attractive effects. But the practice should not become a mania.

To be able to use niters correctly, to make them fill a definite
need and perform a definite task, the photographer must know the
film he uses, know its sensitivity to colors, know which colors react
more strongly on its emulsion and which should be suppressed and
retarded so that other colors may become equally effective. This,
in effect, is nothing less than handicapping one or more of the more
actinically active colors in favor of those which are ''slow in getting
there.77 Thus, if the film records blue too freely, some of it should
be held back. A yellow filter is used for this purpose.

A panchromatic film is, generally speaking, more evenly balanced,
in its response to colors, but its sensitivity to green is slightly lower
than to other colors. To effect balance, all other colors must be
suppressed or retarded slightly in order to give the green color an
opportunity to impress itself on the film. A certain greenish colored
filter is used for this.

The effect which filters have upon certain emulsions may be
clearly understood from the diagrams shown. These are not accurate,
but they tend to interpret the color sensitivity of different emulsions
when a filter is placed in front of a lens.

Fig. 62 Effect of Filters upon Relative Color Sensitivity of Film: A
Typical Orthochromatic Emulsion (in Daylight)

In considering the use of filters, it is most important to realize
that even films of the same type but of various makes have different
characteristics regarding their degree of sensitivity to different colors.
Thus, an orthocliromatic film of one make will respond to certain
colors to a different degree than an orthochromatic film of another
make. The same applies to various makes of panchromatic films.

Fig. 63 Effect of Filters upon Relative Color Sensitivity of Film: A
Typical Orthochromatic Emulsion (in Mazda Light)

Nearly every film manufacturer publishes spectrographs of his re-
spective emulsions, which, if properly read, indicate their relative
sensitivity to color. Some manufacturers have this information avail-
able in the form of numerical tables showing the relative sensitivity in
terms of per cent, 100 standing for " normal7 ' color rendering.

The Agfa Ansco Company offers the following information concerning
color sensitivity as measured by the Agfa Step Color Chart for the same
emulsion:

• Red Yellow Green Blue

In daylight 60 50 30 140

In Mazda light 180 80 40 80

On the other hand, manufacturers of filters supply spectrophotometric
absorption curves of filters which show graphically colors which are trans-
mitted and absorbed by a given filter. A combined study of these data
will yield accurate information as to what results may be expected from
the use of certain filters in connection with certain films. This informa-
tion, however, is not essential for the use of filters except in work of a very
exacting nature. For general use, working familiarity with a film and
filter may be gained by more practical methods.

Filters

Fig. 64 Effect of Filters upon Relative Color Sensitivity of Film: Typical
Panchromatic Emulsion of Medium Sensitivity to Red (in Daylight)

Making Your Own Filter Tests

If a working knowledge of the properties of a film or filter is desired,
a series of exposures on the film with and without the filter is the best
means of getting it. Such exposures should be made with great care and

Fig. 65 Typical Panchromatic Emulsion of Medium Sensitivity to Red (in
Mazda Light)

a record of conditions kept. The first exposure should be made without the
filter and should be based upon a careful reading of a reliable exposure
meter. The series of exposures should be carried out according to a defi-
nite plan:
Film: Rated Speed:

Exp.
No.
1

Light
. Daylight

Filter
None

Meter Lens
Reading Aperture
1 sec. f/6.3

Shutter
Speed
1 second

2 seconds

4 seconds

4 Blank
5

Exposure

*/2 second

l/4 second

7 Blank

Exposure

No. 2

I sec. "

2 seconds

4 seconds

8 seconds

11 Blank
12

Exposure
n

1 second

1A second

Similar procedure may be employed for testing one or two other filters.
The exposed film should be developed in the developer customarily used.
The final proof of the test is in the finished print. The best print obtain-
able should be made from the negative resulting from Exposure No. 1.
Prints from all other negatives should be made in exactly the same way,
the same paper used, the same degree of enlargement, the same exposure
given, the same developer and time of development. When these prints
are finished and dry, they should be compared and studied for color cor-
rection, contrasts and detail rendering.

Fig. 66 Effect of Filters upon Relative Color Sensitivity of Film: A
Typical Panchromatic Emulsion of High Sensitivity to Red (in Daylight), ,

Filters

Fig. 67 Effect of Filters upon Relative Color Sensitivity of Film: A
Typical Panchromatic Emulsion of High Sensitivity to Red (in Mazda Light)

Such study will frequently yield surprising results. It may be found,
for instance, that best results may be obtained without the filter. Or that
the most desirable effect was produced when the filter was used without
increase of exposure. And then again, it may be that the picture was
most interesting when no filter was used, but the exposure halved.

Thus, for instance, it will be found by actual experience that if a
filter, primarily intended to suppress blue rays for which a given film is
too sensitive, is being used effectively in daylight, the same filter will be
found unnecessary for work in artificial light because of its more abundant
yellow and red rays. Obviously, there is no need to filter blue rays from
a light which is in itself deficient in that color. The same would hold
true of work in the late afternoon when daylight becomes more profuse
in yellow light. There would, ordinarily, be no need for a yellow filter.
It must be remembered, however, that although a filter is used to establish
a definite balance of color rendering, the use of the filter is superfluous
where that balance is present either in the light source or the subject.
Thus, if the sky is dark blue, even a light yellow filter will create a cor-
rect color balance on a panchromatic film, and if it be a panchromatic
emulsion of high red sensitivity, no filter will be required to produce such
balance. If the sky, however, be pale blue or grayish blue, a more dense
filter would be required.

Filter Factors

To identify filters by means of their respective factors would be
meaningless, since no filter requires the same increase of exposure for
every film and for every light condition. For this reason, modern filters
are no longer designated by the symbol "x" following a number, like 2x,
3x, 4x, etc. These designations were intended to represent the inc mse
of exposure by two times, three and four times, respectively. Modern
filters are designated by their manufacturers either by a letter, number

or both, and each represents a medium of definitely known power of ab-
sorption or transmission of certain rays of light. Consequently, filter
factor tables should not be taken too literally, for the best of them are
merely intended to give their relative power of absorption or transmission
regarding a definite emulsion. These tables should be used as guides only.
A definite familiarity with the properties of a film can be gained only
through practical application very much in the same measure as is the
case with emulsions, developers, papers, lenses, etc.

While color filters properly used offer a very flexible and definite
control of contrasts and tones, it should be realized that there are other
means with which certain effects may be produced. The making of prints
by enlarging rather than by contact offers an opportunity for holding
back the light from certain areas of the print while permitting it to
print through on other areas. This dodging or shading by means of a mov-
ing hand, finger, piece of black paper, or cardboard enables the skilled
worker to produce quite remarkable effects on the finished print. Thus,
for instance, if one has a negative of a landscape on which a filter has not
been used, a negative possessing all detail and gradation in the foreground
but a corresponding overexposure and whiteness of the sky, the latter may
be successfully printed in or darkened to any degree desired by first expos-
ing the paper for a length of time sufficient to bring out the detail of the
foreground and then interposing a piece of cardboard between the lens of
the enlarger and the portion of the paper containing foreground, letting
the sky print through. The exact technique of dodging and shading is de-
scribed elsewhere. This point is mentioned here to assist any who may
have neglected to use a filter and who wish to improve a picture which
would otherwise appear bare and uninteresting from lack of an appropri-
ate sky background.

Choice of Film and Filter

Those who lack experience in selecting a film and a filter to go with
it to produce certain effects will be well served with Viewing Filters.
These are strictly, as their name implies, visual filters and should never
be used for actual photography. They consist of discs or squares' of col-
ored glass or gelatin mounted between glass. Colors, when viewed
through them, are considerably dulled and impress the eye in terms of
their relative brightness and contrast of tone, approximating the interpre-
tation of the film. These visual filters are available in the form of
monocles, or regular spectacles. By looking through them, the photog-
rapher is in a position to anticipate the effect upon the film before ex-
posure. For work on ortho chromatic emulsions deep blue filters are used,
while panchromatic emulsions require either a muddy yellow or greenish
visual filter. By far the most practical and economical visual filter guide
for the purpose can be had in the form of an inexpensive Filter Test Chart,
furnished by the Eastman Kodak Company. This chart contains eight
transparent samples of the most popular contrast filters and four test
filters (blue, green, yellow and red) through which subjects may be viewed.

If the subject, as seen through the monochromatic filter, appears to
the eye so that one can distinguish the different degrees of brightness of
the various colors, the film and filter indicated under that viewing filter
should be used to secure such rendering. If one cannot distinguish the
various colors, the subject should be viewed through another filter, and so on.
One of these will be found to give the desired color correction. Consider-
able knowledge of rendering color contrasts may be gained from frequent
application of this simple device.

Filters

Fig. 68 Suburban Home

Henry M. Lester

Elmar 35mm, 1/60 second at f:9. Sky Filter. Du Pont Superior Film

What Filters to Use

It is a good policy to follow the suggestions of manufacturers
of photographic equipment as to the type of accessories. They can
very well bear the responsibility for such use as it is to their interest
to help obtain the best results possible. Choice of the type and make
of filters used should be based upon the negative material employed.
If a variety of films is used, one will be best served by the compre-
hensive line of solid glass filters offered by the makers of the Leica
camera. These filters are of excellent quality, thin, uniform and well
mounted. The filter mounts are important, particularly when the
camera is to be used in connection with the various accessories and
attachments for which these mounts are designed. For special pur-
poses, and for specific work with Eastman Kodak emulsions, the
Wratten Light Filters (gelatin mounted between glass) should be
used, they being also of excellent quality and easily available in
unmounted circles fitting the Leica Filter mounts. The Wratten
Light Filters are especially designed for Eastman emulsions artd the
most comprehensive information is available on their effect on these
emulsions.

One would be well served with a complete line of Leica niters
to which special "Wratten Light Filters may be added as required.
However, an impressive array of niters is not needed to turn out
excellent pictures. One or two should be sufficient for all general
work with modern film emulsions. The writers know of several work-
ers who boast of many an excellent picture but of only one filter.

Those who prefer orthochromatic films will be able to go through
life with but one or two filters without missing anything. Leitz No. 1
would be the best choice, while No. 2 might be added to complete the
outfit. The addition of a Graduated Sky Filter might be included
sometimes in preference to the No. 1. The equivalent of these are
the Wratten Kl and Wratten K2.

Users of Panchromatic Films may use more filters, but only if the
scope of their work is greater. Besides the two filters mentioned
above, together with possibly the Sky Filter, the Green Panchromatic
Filter should be used. If Eastman panchromatic emulsions are em-
ployed, instead of the Leitz Panchromatic Filter, the Wratten XI (for
day light) or the Wratten X2 (for artificial light) should be used.

The Leitz Infra Red Filter is a special filter which should be used
in connection with the Infra Red films for special effects. It is one

Fig. 69 The Tower

Blmar 35mm lens, f :9, 1/60, dark yellow filter, Agfa Superpan.

Ernst Schwarz

Filters

of those filters which for special reasons emphatically upsets the color
balance. The Wratten line offers a complete assortment of red niters,
ranging from very pale red to such densities as do not transmit visible
light. The choice of the density should be governed by the purpose
for which it is intended.

A special filter is made by the Leitz Company for elimination of in-
visible ultra violet rays adjoining the visible range of the spectrum.
These filters are intended for use only in high altitudes where these rays
are abundant. At sea-level invisible ultra violet rays are not sufficient to
be detrimental. In small amounts they are not effective, being actually
filtered out by the glass of the lens itself. Never use a filter unless one
is required to eliminate something that is not wanted in the pictures. With
particular reference to the Ultra Violet Filter, commonly known as the
U. V. Filter, it should be remembered that if the filter holds back only
certain rays, the effect of which we want to suppress in the pictures,
whereas it freely transmits all other rays, the exposure need not be in-
creased to compensate for that filter, since those colors that will result in
underexposure are being deliberately so treated by the very use of the
filter. The same may apply to some other filters, particularly those pale
yellow, pale green and pale blue filters which are used for very slight color
correction. While actually even clear glass filters require a theoretical
increase of exposure (about 8%), this may easily be disregarded because
of the available latitude of the film and the improbability of getting a 100%
correct exposure at all times.

Some of the red filters, like the Wratten A or F may be used for
many purposes. Although they are not strictly infra-red filters, since
they do transmit a good portion of the visible part of the spectrum, they
will produce effects quite similar to those obtainable with the regular
infra-red filters when used in connection with Infra-Red films. It will
be simply a matter of degree, but the exposure will be substantially
shorter. These red filters are frequently known as effect filters because
they are used to produce most striking effects of night scenes, moonlight
scenes in broad daylight. In addition, these filters are also known as
haze-filters because they have the rare property of eliminating aerial haze
in distance photography, and in aerial photography. It should be remem-
bered, however, that while these filters are very effective in eliminating
aerial haze, they -will not cut through air filled with smoke, dust, fog
or steam.

While speaking of effect filters, the so-called fog-filters should be
mentioned. These fog filters, unlike the haze-filters, are not used to
eliminate fog from pictures, but, on the contrary, to put it into the picture!
Fog-filters are decidedly misnamed. They are not filters but merely dif-
fusion screens, which are available in a number of degrees of softness or
fog. In skilled hands, these fog-filters produce truly remarkable results.
But, as a matter of general practice, their use is not to be recommended.
The small Leica negative should remain as sharp as possible. If softness
is desired, it should be produced by means of illumination or by using an
appropriate lens at the proper opening. All kinds of fog, and all degrees
of softness and diffusion may be produced on the finished print by skillful
manipulation of the enlarger, and the reader is cautioned against placing
too much faith in such filters as are entirely satisfactory for, say, motion
picture work, but barely desirable in Leica photography.

Just when to use a filter is often something of a mystery to a begin-
ner. Obviously, it is a matter of that great combination of knowledge,
experience and judgment. In order to assist the beginner, the following
list is offered:

Yellow Filters: May be used with either ortho or pan films. Everything
else being equal, a denser yellow filter should be used with the ortho
than with the pan film. These filters are almost exclusively for cloud
effects upon light blue skies. The lighter the sky the darker should
be the filter.

Sky Filters: For use with all films. This filter has a lower half of clear
glass, which from the center gradually changes into a yellow upper
half. The purpose of this filter is to hold back the blue rays emanat-
ing from the sky only, without affecting the lower half of the image
in any way. It requires no increase of exposure. One should be care-
ful in using this filter that the center of the picture coincides with the
line of the horizon. A most useful filter for landscapes and seascapes.

Green Panchromatic Filters: A filter specifically designed to enhance the
comparatively low sensitivity to the green of panchromatic films. Its
effect upon a panchromatic emulsion is similar to that of a yellow
filter upon an orthochromatic emulsion. It holds back not only the
blue, but also the red, to which this type of film is very sensitive. It
is, therefore, useful in the same way for cloud effects, etc. Whenever
Eastman panchromatic films are used, Wratten green panchromatic
filters are recommended for best results. (XI for daylight work and
X2 for artificial light.)

U. V. Filter: To be used only in high altitudes, mountains, etc. Not for
work from an airplane when photographing the earth! The layer of
air acts as an efficient U. V Filter. This filter does in the mountains
what a denser (yellow) filter does at sea level.

Red Filters: For extreme contrasts and effects, where overcorrection is

intentionally aimed for in order to produce dramatic effects. Brilliant
white clouds against a black sky. Moonlight effects with the sun sub-
stituting for the moon. Dramatic sunsets. To be used with pan-
chromatic films only. The darker red filters are designed and intended
specifically for infra red photography with Infra Red film.

Editor's Note.

Our readers will be interested to know that filters having transmission
characteristics and factors similar to those of the Wratten type, are now
available in many of the popular colors in solid glass form. These filters
are made of optically flat glass not affected by temperature or climatic
conditions. They are distributed in this country by the Chess- United Co.,
160 Fifth Avenue, New York City, through their agents and dealers.

Filter Factor Table

The following table of filter factors is offered in the hope that it be
used with a grain of salt. It is deliberately placed at the end of the chap-
ter, trusting that the reader will not use it literally, but merely refer to
it for general guidance and information. The factors are bound to change
with varying light conditions. They should not be followed blindly, but
when used intelligently may be helpful in getting the desired results.

raters

Fig. 71 Moon Over the Empire State

ELmar 50mm, 3 seconds at f:3.5. Photograph taken at 1 A.M.

John T. Moss, Jr.

DuPont Superior Fihn

THE 35 MM

HENRY M. LESTER CHAPTER 4

The 35mm film used in standard motion picture cameras estab-
lishes for the Leica a valuable relationship. Because of the vast
quantities of film which the motion picture industry consumes, the
manufacturers of 35mm film go to no end of trouble to produce the
greatest variety and finest quality of film. This in turn makes avail-
able to the Leica user an unlimited choice of negative material which
the user of larger cameras does not enjoy. "While this is a decided
advantage to an experienced Leica worker, it is frequently confusing
to the beginner.

It may be said, almost without reservation, that the modern
35mm film produced by large manufacturers is of excellent uniform
quality throughout, regardless of its type. However, not all films
are adapted to every kind of work. If they were, there would prob-
ably be no need for some fifty different types of 35mm film available.
Some film emulsions have a wide range of application and may be
•considered more or less universal. The word universal is obviously
a generality and as such is only measurably correct. Other films are
designed to fill a specific need in the more specialized fields of
photography.

Those Leica workers who do not concentrate upon the more
specialized phases of photography, like photomicrography, aerial
photography, elinical work, etc., but who want to obtain excellent
photographs within the scope accessible to all photographic workers,
will find that almost any good film of a standard make will answer
their requirements — provided they will get to know it through con-
stant use and will understand its characteristics and its response
to exposure and development. On the other hand, those who are
doing specialized work should select a film to answer that specific
purposp. In either case, for consistently good results, once a film
emulsion is decided upon, whether it be for portraiture, pictorial
work or copying X-rays, that film should be used always for that
purpose, to the exclusion of all others,

Success in photography, as in all other crafts, is based upon the
ability of the worker to produce definite results. To produce them
consistently the worker must know Ms equipment and materials
thoroughly to make them do what he wants. Therefore : know your
film, learn what it can do and make it fit your purpose.

Part I — Film Selection

The 35mm films should be considered from the following view-
points as the first step in making the selection :

1. Sensitivity to Color . . . From this viewpoint the films are
considered depending upon their response to various colors.
Those that respond or are sensitive to all colors including red are
known as Panchromatic.

Those that are sensitive to all colors except the spectral red are
known as Orthochromatic.

The relative sensitivity of an emulsion to the various

colors can be controlled by means of filters.

Films that are not sensitized to distinguish between colors, except
between black and white, are known as Color-Blind.
Then there are the Special Emulsions required for color photog-
raphy infra-red photography or direct positives.

2. Speed of Emulsion . . . From this angle the films are con-
sidered depending upon the relative amount of light required to
form an image on the emulsion. This classification results in
terming films as fast, medium or slow.

The speed of a given emulsion can be controlled
within certain limits by development.

3. Graininess . . . From this point of view the films are con-
sidered depending upon the size of the grain of the emulsion.
The smaller the size of the grain, the more desirable the emulsion
for Leica work.

Although the size of the grain is inherent in each
emulsion, being a definite part of its structure, its final
size in the negative can be controlled by means of suit-
able development.

4. Contrast . . . From this viewpoint, we consider the emulsions
as to their ability to render comparative degrees of brightness
of the image. If the film is capable of rendering many shades or
gradations of grays between black and white, it is known as
a low contrast or long scale film. If the range of gradations of

Film Selection

Fig.* 72 I Smell Cat!

Fig. 73 Ah, There You Are!

Roland Smith

Roland Smith
99

gray between black and white is not great, the emulsion is known
as one of high contrast or short scale. Generally, the finer the
grain the greater the contrast and the shorter the scale.
Although contrast is substantially built into the emul-
sion, it can be most effectively controlled by exposure
and development skilfully made to depend upon each
other.

5. Latitude . . . Here we consider the film by its ability to react
to various quantities of light admitted to it. It would be just too
bad if every exposure would have to be "on the button", so to
speak, to produce a usable negative. We therefore look to the
emulsion for its ability to yield usable negatives with a certain
amount of under or overexposure. Latitude is important to us
not only because of the ever present danger of over or under-
exposure, but also because of the definite effect which we fre-
quently want to produce by over and underexposure. Generally,
the finer the grain of an emulsion, the less its latitude.

The latitude of the film is one of its inherent charac-
teristics which cannot be readily controlled.

Selection to Fit the Purpose

An important factor of successful Leica photography which is
not generally appreciated and understood is the necessity to choose a
film to fit a definite purpose.

The general level of quality of Leica work could be raised con-
siderably if the worker, instead of asking the dealer for the best and
most expensive film, would consider these questions :

What is the film going to be used for?

In what developer will the film be processed?

What size enlargements will be required?

What type of paper will the enlargements be printed on (glossy,

mat, rough) ?

The size of the grain, as is generally known, increases with the
speed of the emulsion. There is a vast field of photography where
extreme speed of the film is not as essential as fineness of grain. The
selection of the emulsion should therefore be made with a preference
for fine grain rather than speed. This is made quite feasible by the
growing availability and popularity of extremely fast and sharp
lenses. However, where sufficient light is not available, or quick
action must be recorded, fast films must be used and one must be
willing to sacrifice the size of the grain and be satisfied with a smaller
enlargement for the sake of getting the picture, which would be im-
possible without the fast film.

100

Film Selection

Types of Film

With a view to simplification of the multitude of emulsions avail-
able on the market, a classification into five groups is offered. It
should be remembered that while each of these grouped emulsions
has its own distinctive characteristics, they have a good deal in
common, and the grouping is offered for simplicity. Also as a means
of expediency, not all the emulsions are being listed, but only those
whose popularity makes them readily available in either bulk or
daylight loading packages.

Group No. 1 Panchromatic Emulsions (Fast)

Agfa Superpan

DuPont Superior

Eastman Kodak Super-X

Eastman Kodak Super- Sensitive

Gevaert Panchromosa

Perutz Peromnia, etc.

The films of this group are fully panchromatic, being sensitive to
all colors, including red. These emulsions are not alike in their
relative response to the various colors of the spectrum. For ex-
tremely critical color corrections spectrographs of each emulsion
should be consulted. (These spectrographs are readily obtainable
from the respective manufacturers.)

The most distinguishing feature of the emulsions of this group
is their speed: their all-over great sensitivity to light, both daylight
and Mazda. Their speed rating in daylight is 23° Scheiner or 24 to
32 "Weston, and in Mazda light 20° Scheiner and 16 "Weston. The
emulsions of this group are of the low contrast and soft gradation
type. The degree of contrast of these films can successfully be con-
trolled in development. They possess excellent latitude and will yield
usable negatives resulting from several times under or overexposure.
Their graininess is consistent with their high speed.

Group No. 2 Panchromatic Emulsions (Medium Fast)

Agfa Finopan

DuPont Micropan

Eastman Kodak Panatomic *

Perutz Perpantic, etc.

The films of this group are fully panchromatic, the same as
those in Group No. 1, being sensitized to all colors. The particular
distinction of these emulsions is the exceptional fineness of grain
combined with good all-over sensitivity, which places them in the
medium fast class. Their speed rating averages from 18° to 20°
Scheiner or from 8 to 16 Weston in daylight, and from 14° to 17°
Scheiner or from 4 to 8 "Weston in Mazda light.

101

The latitude of the films of this group is not as great as that of
Group One but still considerable, and can be controlled in develop-
ment. Generally, films of this group are of the "brilliant'7 type,
yielding negatives of high contrast and consequently of a shorter
scale.

Group No. 3 Orthochromatic Emulsions

Agfa Plenachrome
Gevaert Express
Mimosa Extrema
Perutz Neo-Persenso, etc.

The emulsions of this group are fine representatives of the
popular orthochromatic type. They are sensitive to all colors, except
the spectral red, with a high sensitivity to green. These films com-
bine extreme fineness of grain with extreme speed to daylight.
Their definition is excellent and the gradation quite complete. They
belong to the " brilliant " type characterized by high contrast and
a medium long scale. Their speed rating in daylight is approximately
Schemer 23°, Weston 24.

Fig. 74 Montevideo, Uruguay
102

Burton Holmes

Film Selection

Group No. 4 Color-Blind Emulsions

This group includes only positive film, which is produced by
every manufacturer of negative film. Positive film is sensitive only to
the blue and violet colors of the spectrum. The distinguishing fea-
tures of positive film are its extremely fine grain, high resolving
power, excellent definition and extremely high contrast. The length
of its scale of gradation is rather short, but this depends greatly upon
exposure and developing procedure. The speed rating for positive
film in daylight is about Scheiner 8°, "Weston 1. It is difficult to give
its speed rating for artificial light because it is entirely dependent
upon the amount of blue light in the particular light source.

Group No. 5 Special Emulsions

A. Films for Color Photography

Agfacolor

Dufaycolor

DuPont Bi-Pack

Eastman Kodak Zulcras Bi-Pack

Eastman Kodak Kodachrome

Lumiere Film Color, etc.

Each of these films represents a definite system in itself, and

Fig. 75 The Welder

Ed. Schaefer
103

complete information pertaining to their characteristics is beyond the
scope of this chapter.

B. Infra-Red Films

Agfa Infra-Red
DuPont Infra-D
Eastman Kodak K

These films are panchromatic with the sensitivity to red extend-
ing beyond the visible red portion of the spectrum. Their sensi-
tivity extends to light waves of from 700 to 1000 millimicrons.
Without special filters these films can be used as par speed pan-
chromatic emulsions. It is difficult to give the numerical speed rating
of these films when used with special infra-red light filters. "Without
these special infra-red light filters they rate about 17° Scheiner or
8 Weston, in daylight; but these figures are to serve merely as ap-
proximations. Infra-red films are rather coarse grained, and their
gradation, contrast, color properties depend largely upon the subject
matter and use to which they are put.

0. Agfa Reversible Superpan

This is an interesting new emulsion intended for direct positives
secured by reversal. This film cannot be developed to a negative.
It was designed for direct production of positives to be viewed as
stereo pictures by projection or by transmitted light. Another in-
teresting application of this film material is for production of paper
negatives or enlarged negatives by direct projection. Its speed rating
in daylight is 20° Schemer or 16 Weston, and in Mazda light 19°
Scheiner or 12 Weston. See page 126 for processing formulas.

Emulsion Speed Values

Definite speed ratings for each emulsion are not given here. Speed
ratings are merely relative values. They are useful only in connection with
given exposure meters. Every good exposure meter is accompanied by a
complete list of speed ratings of almost every film known. One should
refer to these lists for such specific information and apply it judiciously.

The various emulsion speed values now used cannot, in general, be
compared directly with each other, except possibly H & D and the Weston
speed values, for the reason that they are based on entirely different
principles.

The Scheiner and Din speed numbers have no definite relation to each
other nor to the other speed values except for emulsions having the same
characteristics which, however, are quite different for the various kinds
of commercial films or plates.

104

Film Selection

Fig. 77 After the Catch

Manuel Komroff

Hektor 50mm lens, 1/100 second at f :4.5. DuPont Superior film

To give a rough idea of the relation of the various speed values a
comparison is given below for a type of film having the same character-
istic as an ordinary commonly used film, but as stated above, the relative
values do not hold for other types of emulsions and must, therefore, be
used with due caution.

For example, a report of an actual test shows that 26° Scheiner may
be equivalent in Din degrees to any value from 12/10° to 17/10° Din,
which corresponds to a ratio of over 3 to 1 in sensitivity. Further, 18/10°
Din may "be equivalent in some emulsions to 65 Weston and in others to
24 Weston.

Comparative Table of speed ratings of various Systems.

CAUTION — Do not use this table without reading above.

Relative

Value

18.3
23.4
29.8
37.9
48.3
61.6
78.5

100

127

162

207

264

336

426

Weston

Scheiner

DIN

7/10
8/10
9/10
10/10
11/10
12/10
13/10
14/10-
15/10
16/10
17/10
18/10'
19/10
20/10

H&D

159

200

252

318

400

504

635

800
1000
1270
1600
2020
2540
3200

105

Following are suggestions of the type of film to be used for best
results in different kinds of work. The recommendations refer to
groups of similar emulsions (see above) ; the choice of any one film
is left to the worker:

Group

of Film

Suggested

Depending on light conditions,
density and color of filters em-
ployed 1 or 2

In daylight 3

In artificial light 1

Exteriors alone 3 or 2

Both exteriors and interiors. ... 1 or 2

Including child and animal pho-
tography 1

Blue-prints (with red filter) 2

Black and white drawings,
charts, line work, documents and
other printed matter in black and
white where good contrast is re-
quired 4

Coins, stamps, paintings, fabrics
or any other small or large ob-
jects containing color or requir-
ing use of filters for better con-
trast 2

Photographs in good condition. 3

Photographs, old or faded where
use of red filter is required 2

Transparencies, black and white,
finger prints, X-rays, etc 3

Transparencies containing color 2

Aerial

Action and Sport

Architectural

Candid

Copying

106

Film Selection

Entomology (insects etc.) 1 or 2

Flowers-Plants-Gardens 1 or 2

Geology (minerals) 2 or 3

Landscape and Pictorial If true color correction is re-
quired 1 or 2

If great enlargements and fine

grain are preferred 3

Medical For general use, and for adverse

light conditions 1

If adequate illumination is avail-
able 2

Dental work 1

Dermatology 3

Ophthalmology 1

Night and Stage 1

Photomicrography If color filters are required. .... 2

If no color filters are required. . 3

For living organisms 1

Portraiture If adequate illumination is avail-
able 2

For adverse light conditions. ... 1

General Use For beginners 3

If outdoor in daylight 3 or 2

If entirely or partly indoor, or
entirely or partly under artifi-
cial light 2 or 1

Natural Color 5 A

Infra-Red 5 B

Reversal Transparencies 5 C

Daylight Loading and Bulk Film

All films mentioned here, and many others, are available in two

forms :

1. Daylight loading spools or cartridges containing from
30 to 36 exposures.

2. Bulk in rolls containing 25, 50, 100, 200 or 400 feet.

107

The daylight loading packings are lengths of film from 5 to 6 feet, cut
and trimmed ready for loading into the camera. Some packings have a
paper leader strip and are used in connection with the regular Leica cam-
era magazine. Others are sold in the form of ready-to-use cartridge maga-
zines which are loaded directly into the camera. For convenience and ready
availability daylight loading packings are most desirable.

Bulk film has many advantages, including that of considerably lower
cost. When purchased in original manufacturer's packages it is more
likely to be free from scratches and abrasion marks than film obtained in
daylight loading units. Those who need and appreciate uniformity of film
will find that bulk film offers it, since a roll of say 100 feet is the same
throughout, and once its characteristics become known to the user, they can
be depended upon as long as this supply is used. Bulk film also offers the
advantage that it can be cut to any desired length, enough for forty ex-
posures or perhaps only five. It is recommended to buy bulk film in so-
called "automatic camera" packages consisting of solid metal spools, which
provide a most satisfactory method for storing and handling film, protect-
ing the emulsion and edges against excessive contact with fingers. BULK
FILM SHOULD BE HANDLED WITH EXTREME CAEE and its use
should not be attempted by workers lacking the necessary experience.

Part II — Film Exposure

The last decade has witnessed an interesting trend in the field
of photography. Both the professional and amateur workers had
gradually become exposure conscious. They began to realize that
every important characteristic of the finished photograph takes its
root at the time the exposure is made, and that the desired result de-
pends upon their ability to coordinate judicious exposure with skilful
development of the negative.

The Leiea camera is in a great measure responsible for this
realization. Leica photography has established a definite system based
on the successful application of a number of principles. One of these
principles is a certain uniformity of exposures, since as many as
thirty-six negatives are usually developed at the same time, and in-
dividual negatives cannot be controlled in the development.

This requirement of Leica photography brought about the in-
terest in normal exposure. Normal exposure is that which places
the range of brightness somewhere in the middle of the limits of the
latitude of the emulsion. In terms of ,§yery day work normal ex-
posure strikes a compromise between tfie light and dark portions of
the subject so that the bright portions are not overexposed while

details in "f"^01 QlnarlA^xrc! QT»/S T»onr»T»rl n/--! -f/-v/-v

108

Film Exposure

Prom this point, within the limits of the latitude of a given
emulsion, a range of exposures favoring either the shadow details
or the highlights is available, depending upon whether the pre-
dominant part of the photograph is to bring out the dark or light
portion of the subject. Which brings us to the matter of correct
exposure. That exposure is correct which puts on film exactly what
is wanted in the picture.

A great variety of exposure meters and tables is available to
assist us in obtaining normal exposures. But correct exposures do
not necessarily mean normal exposures. While normal exposures
are within reach of every owner of a reliable exposure meter, cor-
rect exposures require judgment and skill on the part of the pho-
tographer— the knowledge of when and how to use over or under-
exposure to get what is wanted in the picture. This knowledge
comes with practice and experience.

Exposure Meters

Exposure meters are essentially of three types:

1. Exposure tables and calculators are helpful guides to normal exposures
based on compiled actual experiences. Some of these are available in
the form of direct tables which suggest approximately normal exposures
for different emulsions and for various subjects, taking into consideration
time of day, location, season, weather, etc. Others are put up in the
form of slides or discs made of cardboard, celluloid, etc. Then there are
some in the form of booklets containing in addition to suggestions con-
cerning exposures a variety of information, references, etc. The chief
merit of all of these lies in their providing some basis for arriving at a
more or less normal exposure.

2. Visual exposure meters which are frequently known as the "extinction
type" require sighting the subject through a ground or tinted glass
screen while the amount of light admitted is gradually reduced to a
minimum. When that minimum is reached a scale indicates the desired
data. The greatest disadvantage of this type of meter is the impossi-
bility to assume a standard sensitivity of the eye to light. Its chief
advantage is its ability to give readings in extremely unfavorable light
conditions of interiors and night photography. Any one of these instru-
ments, if used consistently and with judgment, will provide usable in-
formation as to normal exposure.

3. Photometric exposure meters are the latest and to date most accurate
and dependable means for ascertaining normal exposures. They are
usually made as instruments of great accuracy and precision, and should
be handled as such. The instruments are built around a photoelectric
cell which converts light energy into electrical energy, which in turn
activates extremely sensitive miliammeters calibrated in terms of light
values. Such popular photoelectric instruments as the Weston or the
Photoscope, though comparatively expensive, belong actually to those
self-liquidating investments which earn their price through constant
economies of film, elimination of uncertainty and securing results. "

109

Fig. 78 Weston Photoelectric
Leicameter, New Model No. 650

Any of these exposure meters when used strictly in accordance with
manufacturer's instructions will yield results of surprising accuracy. Each
has its own advantages and a careful comparison of them should be made
before deciding which one will answer individual requirements. It is difficult
to make specific recommendations because of the vastness of the field which
Leica photography covers today.

There are no factotums in photography. The more one knows about
photography the more difficult it becomes to point specifically to any one
film, exposure meter, lens, developer, paper and attach the term "universal"
to it. Only a careful examination of the product and scrutiny from the
viewpoint of what it is expected to perform will determine its usefulness.

No matter what the relative merit of any of these meters may be, it
is safe to state that the consistent use of any one of them will yield results
far superior to those obtained by guesswork.

How to Use an Exposure Meter

An exposure meter, very much like a lens, has a very definite
field coverage, varying with the make. The manufacturer supplies
this information with every instrument. The area covered should be
thought of as the base of a cone whose apex is in the center of its light
sensitive surface. The angle of this apex varies anywhere from 50°
to 70°.

It should be remembered that a meter has no power of selectivity.
For instance, if a reading is taken of a dark object back of which
is a light surface, the meter will give a reading proportionate to the
relative amount of light and dark portions of the entire area which
it "sees". One should endeavor, therefore, to take a reading by
holding the meter as close as possible to the object for whose detail
the exposure is to be made. The meter should be held in a manner
to prevent its shadow being cast on the area under observation.

110

Film Exposure

When taking the reading of small objects occupying only a small
portion of their background, the proper way to secure a correct read-
ing is by the method of substitution. A sheet of paper or fabric of
a color and brightness approximating that of the small object should
be placed over the object and its background and a reading secured
from that. For instance, if teeth are photographed and the meter
directed on the face or mouth, considerable overexposure of the teeth
would result, because the skin and lips are darker than the teeth.
However, if a piece of ivory tinted paper is placed over the face and
the meter directed on that, a correct-exposure of the teeth will result,
while the lips and skin will be somewhat underexposed. This example
is quoted merely in the hope that it will assist in the judicious use
of exposure meters. Here again, the purpose of the picture must be
borne in mind.

Needless to say, instructions accompanying every instrument
should be read and followed carefully.

Pig. 80 Doug

Barbara Morgan
Summar 50mm lens,
1/100 second at f:6.3
DuPont Superior film

How to Make Exposures Without an Exposure Meter

If an exposure meter is not readily available, or if there be no time to
use one, the following method is recommended:
Set your shutter speed at 1/30 or 1/40 of a second.

If the sun is shining unobstructed by clouds, make three exposures of the
subject: one with the lens set at f :6.3, one at f :9, and one at f :12.5,
If the sun is obstructed by clouds (no shadows cast), take three exposures
of the subject: one with the lens at f :6.3, one at f :4.5, and one at f :3.5 (or
larger opening1 if available).

This rule-of -thumb method seldom fails to produce at least one usable
negative out of three taken. When in extreme doubt make a fourth exposure
either at a larger or smaller opening than indicated above. Remember your
film is the least expensive part of your equipment while opportunities for
pictures rarely repeat themselves.

Ill

Exposures for Photoflash

Average Distance Covered by One General Electric Mazda Photoflash

Lamp in a Eeflector

Approx. Distance of Lamp to'Subject
Ortho Film Super-sensitive Pan
Group No. 3 Group No. 1 Film

5 ft. 7 ft.

7 10

Diaphragm

Opening

f:18

f:12.5

f:9

f:6.3

f:4.5

Size of
Photoflash
Lamp
No. 10
No. 20

No. 10
No. 20

No. 10

No. 20

No. 10
No. 20

7
10

15
20

20
25

15
20

20
30

25
35

These figures are based on a room with medium colored walls and
ceiling. Where pictures are made outdoors or under adverse conditions
at the greater distances, use the next larger diaphragm opening or reduce
distance from lamp to subject to about 70 per cent of that shown.

Part III — Film Development

Development with Relation to Exposure

Leiea negatives will produce excellent enlargements if they meet
two requirements :

1. Fineness of grain.

2. A comparatively low degree of contrast.

Both of these conditions can be met by carefully selecting the
negative material and by coordinating the exposure with the de-
velopment.

Leica negatives must be processed with low energy developers
which act gently and slowly. Development is carried out on the
time-and-temperature principle.

Most fine grain developers adopted for Leica work are carefully
and scientifically compounded to act uniformly and to produce pre-
determined results. It is not necessary to delve into details of sensi-
tometry to obtain such predetermined results. To provide a means

112

Film Development

of comparison of densities and contrasts, scientists have evolved a
definite system. The unit in which the functional dependence of
density, contrast and exposure is expressed is the term gamma (y)
which is defined as a numerical expression for the contrast of the
negative obtained from a range of given exposures carried out in a
given developer in a given time.

Depending upon the size of the finished enlargement, the gamma
of Leica negatives should vary between .6 to .8. The lower value,
which stands for lo\ver density and contrast, should be aimed at for
greater enlargements; while the higher value for smaller enlarge-
ments. Gamma of approximately .7 will be found excellent for all-
around purposes, and it is the gamma value of .7 on which the
time-and-temperature units should be based for the various fine
grain developers.

Density and contrast of a negative corresponding to gamma value
.7 are based upon normal exposure. Consequently, underexposures
with the same development will result in higher contrast and less
detail in the shadows; while over exposure under the same developing
conditions will result in lower contrast and more detail in the
shadows.

The time-and-temperature factors for a given developer to
produce gamma .7 stand for minimum development. This minimum
is necessary to assure fineness of grain and low contrast. If de-
velopment is carried beyond that minimum, it is likely to increase
both graininess and contrast. In order that development be held
to this minimum and still bring out as much detail in the negative
as possible LEICA NEGATIVES MUST BE FULLY EXPOSED. Briefly:
OVEREXPOSE — UNDERDEVELOP ! . . . within reason of course. To put
this in terms of practical application, the film speed ratings usually
published should be considered as somewhat over-rated, and for best
results the films should be used at ratings slightly below the ' ' official ' ?
ratings.

Developing Equipment

The equipment for developing Leica film is extremely simple, easy
to handle and with proper care will last a lifetime.

For convenient development of Leiea film there are two tanks, the
Correx and the Reelo. There is also a glass developing drum. Instruc-
tions for handling accompany each one. The tanks should be used pre-
ferably in all cases, except for reversal where the developing drum alone
or in connection with one of these tanks is recommended. The greatest
advantage of developing Leica films in one of these tanks is the fact that
no dark room is needed for the process. Once the film is transferred into
the tank (this can be accomplished in a changing bag), the development
and subsequent handling do not require darkness.

113

Fig. 81 The Reelo— All Bakelite Developing Tank

These two tanks differ from one another by the method in which sepa-
ration of the film layers is accomplished. In the Correx tank the film is
separated by means of a celluloid apron with studded edges, while in the
Reelo tank it is separated by the grooved spool. The tanks are equally
effective and selection between them is a matter of personal preference.

The capacity of the Correx tank is about 500.0 cc, or 16 ounces; and
that of the Reelo about 400.0 cc, or 12 ounces.

Fig. 82 Glass Developing
Drum and Tray

Fig. 83 The Correx
—All Bakelite De-
veloping Tank with
celluloid Studded
edge Apron and
Thermometer

114

FUm Development

Fig. 84 Method of Winding Film upon
Reelo Spool.

Developers

Those who wish to process their films themselves may use any one of
the prepared ready-to-use developers on the market, which are available
either in powder form or in concentrated liquid form. These preparations
will give excellent results if used strictly in accordance with manufacturer's

directions.

A more economical and possibly more practical way to produce
excellent negatives is to, prepare one's own developer as well as other
solntions required for processing Leica negatives. A few simple
chemicals, a scale and a few graduates, are all that is necessary.

The number of formulas offered for fine grain development is
enormous. A careful study of them reveals the important fact that
in addition to some processes which have purely experimental merits,
there are only two classical basic formulas available. Others are
merely modifications of these two:

1. The Metol Hydroquinone Borax type.

2. The Paraphenylene Diamine type.

The first type represents a developer which, as far as miniature
camera work goes, can be termed the maximum energy developer.
It will bring out details in shadows and underexposed portions of
the negative to a remarkable degree, while it will produce granu-
larity of sufficient fineness to yield excellent enlargements up to
8x10".

The second type is a low energy, extremely fine grain developer
which requires a fuller exposure than the first type, but in return will
yield negatives of such fine grain, excellent definition, and low con-
trast that enlargements of 16x20" can easily be obtained.

Reference to fine grain performance of these two developers is made
specifically in connection with films of Group 1, which due to their speed
have an inherently coarser grain structure.

115

events with the Leica — Barbara Morgan designed a series of fifteen different montages of
various school activities. This is an example of paste up montage — the simplest "type using
many individual pictures.

Developing Formulas

The Metol-Hydroquinone -Borax type of fine grain developer is
represented by the classical formula known as Eastman Kodak D-76,
or its derivative the Modified E.K.D-76, also known as Buffered
Borax.

E.K. Formula D-76

Avoirdupois Metric

Water (about 125°F. or 52°C.) 24 ounces 750.0 cc

Metol 29 grains 2.0 grams

Sodium Sulphite, desiccated 3 1/3 ounces 100.0 grams

Hydroquinone 73 grains 5.0 grams

Borax (the 20-Mule Team variety) 29 grains 2.0 grams

Cold water to make 32 ounces 1.0 liter

Dissolve the chemicals in the order given.

Use without dilution.

Develop 16 to 22 minutes at 65 °F. or 18 °C. for films of Group 1 or 3.

Develop 12 to 18 minutes at 65 *F. or 18 °C. for films of Group 2.

This formula can be re-used and the quantity is sufficient to develop from 8 to 10 Leica film

lengths.

Modified E.K. Formula D-76 (Buffered Borax Negative Developer)

Avoirdupois Metric

Water (about 125°F. or 52°C.) 24 ounces 750.0 cc

Metol 29 grains 2.0 grams

Sodium Sulphite, desiccated 3 1/3 ounces 100.0 grams

Hydroquinone 73 grains 5.0 grams

Borax (the 20-Mule Team variety) . . 29 grains 2.0 grams

Boric Acid, crystals 203 grains 14.0 grams

Cold water to make 32 ounces 1.0 liter

Dissolve the chemicals in the order given.

Use without dilution.

Develop 20 to 22 minutes at 65 °F. or 18 °C. for films of Group 1 or 3.

Develop 16 to 18 minutes at 66 °F. or 18 °C. for films of Group 2.

This formula can be re-used and the quantity is sufficient to develop from 8 to 10 Leica film

lengths.

The two developers given above should be used for films of Group 1 in
all cases where it is known that the film has received the minimum possible
exposure due to adverse light conditions (such as encountered in stage,
night, candid and actions photography).
They are excellent standard developers for all films of Group 2 and 3.

The Paraphenylene Diamine type of fine grain developer is em-
bodied in a comprehensive set of four formulas designed by Dr. Sease
of the DuPont Film Laboratories. These four formulas are remark-
able for their delicately balanced -proportions of the same three in-
gredients: Sodium Sulphite, Paraphenylene Diamine and Glycin,
with the latter gradually increasing :

118

JrlLm Development

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119

Formula number 3 should be considered standard.

Formula No. 1, which yields the finest possible grain, requires from
three to four times the normal exposure for the Superior (Group 1 or 3)
film or the Infra D (Group 5B) emulsion but requires little or no increase
of exposure for the Micropan (Group 2) film.

Formulas No. 2, 3 and 4, which yield very fine grain (the finer the
less Glycin the formula contains), require about two times the normal
exposure for the Superior (Group 1 or 3) film or the Infra D (Group 5B)
film, but require little or no increase with Micropan (Group 2).

These requirements for overexposure should be considered as merely
approximate and as referring actually to minimum exposures when these
films are used under inadequate light conditions. One may interpret the
latent image formed on the emulsion as having a certain amount of in-
ertia which is greater the lower the energy of the developer. Thus the
greater the so-called threshold value of the light that strikes the emulsion,
the easier it is for these low energy developers to "pull up" the image.
Consequently when exposures are made in full brilliant light, the require-
ments for overexposure stated above are not as great as those under
adverse light conditions.

Compromise Developers

Neither of the two types of developer described above is entirely
satisfactory for certain kinds of work where photographs taken under
extremely poor light conditions must be considerably enlarged. Such
a situation is frequently encountered in stage, action and candid
photography. For such purposes ' £ compromise ? ' formulas were
evolved which produce excellent shadow detail, gradation and con-
trast, combined with exceptionally fine grain — in cases where only
minimum exposures were possible.

Two such formulas are offered, either of which is a modification
of Dr. Sease No. 3 formula :

Pyro Fine Grain Formula for Not Fully Exposed Negatives

Avoirdupois Metric

Water (about 135° F. or 57° C.). • 24 ounces 750.0 cc

Sodium Sulphite, desiccated 3 ounces 90.0 grams

Paraphenylene Diamine 146. grains 10.0 grams

Boric Acid 14^ grains 1,0 gram

Cold water to make 32 ounces 1,0 liter

Dissolve chemicals in the order given.

Directly before "using add to every SGOcc (16 ounces) of the above solution;

Pyro Crystals 43J/2 grains 3.0 grams,

filter and cool to 65° F. or 18° C.

Develop 30 minutes for films of Group ] or 3.

This developer cannot be re-used after addition of Pyro.

Store it without Pyro.

The other compromise formula is based on the well known property of
Metol to bring out shadow detail and gradation.

120

Film Development

Metol Fine Grain Formula for Not Fully Exposed Negatives

Avoirdupois Metric

Water (about 125° F. or 50° C.) . . . 24 ounces 750.0 cc

Paraphenylene Diamine 146 grains 10.0 grams

Glycin 73 grains 5.0* grams

Metol 88 grains 6.0 grams

Sodium Sulphite 3 ounces 90.0 grams

Cold water to make 32 ounces 1.0 liter

Dissolve chemicals in the order" given.

Use without dilution.

Develop 18 minutes at 65° F. or 18° C. for films of Group 1 or 3.

Develop 12 minutes at 65° F. or 18° C. for films of Group 2.

This formula can be re-used and the quantity is sufficient to develop from 8 to 10 Leica

film lengths. It definitely improves with age and use.

The developers described cover practically the entire range of
Leica photography, and although there are hundreds of fine grain
formulas offered almost every day, as matters stand now these should
be considered best suited to successful Leica photography. These
developers were chosen because of their simplicity, limited number of
ingredients, for their comparatively rapid action and for their de-
pendability. If used strictly in accordance with instructions they
can be depended upon for consistently uniform negatives.

Although the following statement holds true of almost every
phase of photographic procedure, it is of particularly great impor-
tance in connection with the preparation and use of developers : A
person not following a recommended procedure is, at present, enter-
ing* a field of research where definite results cannot be promised.

Conservative use of developers which can be re-used permits the
development of 8 to 10 Leica rolls per 100(XOcc (32 ounces) of de-
veloper with an increase of one minute developing time per roll
processed, i.e., one minute increase for the second roll, two minutes
for the third roll, etc.

Any one of the above formulas (except the Pyro "compromise"
formula) can be re-used within reasonable standing periods, but exact
figures as to their keeping qualities would be of little direct value because
conditions of use and storage differ widely.

Between developments the solutions should be stored in nearly full
well-stoppered amber glass bottles with a special label provided for mark-
ing the developer every time it is used. The developer should be poured
back into the original bottle after each use, until it has been used on 8 to
10 rolls, after which it should be discarded or set aside for "priming" the
next batch of developer.

' It is worth noting" that most fine grain developers produce finer grain
and lower contrast the older they are or the more they have been used.
Most freshly prepared developers work more energetically than those some-
what ag-ed and used. The fresh solutions have that "fire" in them; and
for those who wish slightly softer results and finer grain it is recom-
mended that they "prime" the developer either by adding some 25% of

121

the same developer ready to be discarded, or by developing in the fresh
developer a length of say 5 to 6 feet of fogged film. This produces a
certain amount of oxidation in the developer which takes the "fire" out
of it and softens its action.

Temperature of Developers

Suggestions given in every developer formula for a temperature
at which, the development is to be carried out should be followed
strictly. At temperatures below those indicated the developing agents
may be partly or completely inactive; while at temperatures higher
than those indicated the rate of development may be accelerated with
resulting increase in graininess, density and contrast.

Agitation

As a general rule continuous and vigorous agitation is definitely
to be avoided when developing for finest grain. Continuous agitation
increases the rate of development, which actually should be compen-
sated for by shortening the time. However, this would require a
careful study of systematically developed test strips to insure uni-
formity of results, which would depend upon the type of agitator,
its speed, direction, etc.

Occasional gentle agitation every three to five minutes, however,
is not only recommended but urged. Such agitation does not increase
the rate of development nor affect the time indicated, and is required
to prevent streaking along the perforations of the film.

The Short-stop and the Fixing Bath

Before proceeding with the details of actual development, one should
be familiar with the only other two solutions required for complete pro-
cessing of Leica films:

The Intermediary Short-stop and Hardening Bath. The following solu-
tion seems to have many features which should make it indispensable in the
processing of Leica films:

Intermediary Short-stop and Hardener

Avoirdupois Metric

Water 16 ounces 500.0 cc

Chrome Alum 145 grains 10.0 grams

Sodium Bisulphite 145 grains 10.0 grams

Dissolve Chrome Alum completely before adding Sodium Bisulphite ;

stir until Sodium Bisulphite is completely dissolved.

Use without dilution.

This solution should be used at the same temperature as that of the

developer.

Film should be left in this bath for five minutes.

This solution should be prepared just before required and discarded

once used.

Actual use of this short-stop on hundreds of rolls of Leica films proved
its value. It gently checks development and gradually hardens the emul-
sion, the hardening process being continued in the acid fixing bath which
follows. This intermediate bath seems to correct the acidity of the subse-

122

Film Development

quent acid fixing bath, to a degree which eliminates the danger of reticula-
tion at that point.

The hardening properties of this intermediate bath are such that
negatives treated in it are almost impervious to scratches. It accelerates
final drying of the film by contracting the layer of gelatine to its mini-
mum, thus expelling as much moisture as possible. The emulsion of a
negative treated in this solution and the subsequent acid fixing bath shows
a remarkably glazed surface which makes it almost difficult to distinguish
the emulsion side from the back of the film. This glaze is proof not only
of sufficient hardness of the emulsion and fineness of grain, but also of the
absence of reticulation.

The Acid Hardening Fixing Bath. This is the final solution required
for processing Leica films and its purpose is to dissolve the unexposed
portions of the silver and thus render it insensitive to light. Another
^ function, of, .this fixing bath is to harden the emulsion.

While the packaged form of acid fixing powders which merely requires
solution in a given quantity of water is quite satisfactory, far superior and
consistently satisfactory results are obtained by the use of the newest
formula offered by Eastman Kodak Company:

Acid Hardening Fixing Bath far Films
Formula E.K. F-5

Avoirdupois Metric

Water (at about 125° F. or 52° C.) . . . 20 ounces 600.0 cc

Hypo (pea crystals or rice crystals) . . 8 ounces 240.0 grams

Sodium Sulphite, desiccated y2 ounce 15.0 grams

* Acetic Acid, 28% pure.... l!/2fl. ounces 47.0 cc

Boric Acid, crystals l/4 ounce 7.5 grams

Potassium Alum y2 ounce 15.0 grams

Cold water to make 32 ounces 1.0 liter

*To make 28% acetic acid from glacial acetic acid, dilute 3 parts of glacial acetic acid
with 8 parts of water.
Directions for mixing:

Dissolve the Hypo in about one-half the required volume of water ; then add the
remaining chemicals in the order given, taking care that each chemical is dissolved
before the next is added. Then dilute with water to the required volume.
The film should be left in this hypo bath for 10 minutes (temperature should be

- preferably 'the same as that of the developer) , and it is frankly recommended to use
the hypo for fixing of film once only, after which it may be collected in a separate
bottle for fixing of paper. This may be considered by some as somewhat extrava-
gant, but it should be worth while to know that this final step in processing some
thirty negatives will insure their longevity, -which greatly depends on the freshness
and strength of the hypo.

For those who require larger quantities of acid fixing bath it is rec-
ommended that they keep a separate solution of straight Hypo and a
separate Acid Hardener Stock Solution, mixing them in proper proportions
just before using. This results in fresher solution when required:

Acid Hardener Stock Solution
Formula E.K. F-5a

Avoirdupois Metric

Water (at about 125° F. or 52° C.)... 20 ounces 600.0 cc

Sodium Sulphite, desiccated 2^ ounces 75.0 grams

Acetic Acid, 28% pure ll/2 fl. ounces 235.0 cc

Boric Acid, crystals 1 *4 ounces 37.5 grams

Potassium Alum 2*/2 ounces 75.0 grams

Cold water to make 32 ounces 1.0 liter

Dissolve chemicals in the order given, taking care that each chemical is dissolved

before the next is added.

Add slowly one part of the cool Acid Hardener Stock Solution to four parts of cool

30% hypo solution (2^ pounds of hypo per gallon of water) while stirring the latter

rapidly.

123

Washing the Film

After fixing, the film should be thoroughly washed to remove all traces
of Hypo, otherwise the negatives may in time develop stains. Washing is
best carried out while the film is still in the developing tank. A steady
stream of water, not colder than 65° F. (18° C.) nor warmer than 70° F.
(21° C.), should be permitted to run into the tank through the opening in its
cover for not less than 20, preferably for 30 minutes. If it be important
to wash the film quickly, it is suggested to proceed as follows: Fill the
tank with water, agitate it for one-half to one minute, pour the water out.
Repeat this operation six or seven times. The film ought to be free from
Hypo at the end of this procedure, and ready for drying.

Drying the Film

The film should be carefully removed from the developing reel and
hung from one end by means of a clip. It is best to suspend the film so
that it will not come in contact with the wall or other objects while drying.
With a Viscose Sponge or soft clean chamois, wetted and thoroughly
squeezed out, the excess water should be wiped carefully off both sides of
the film in one slow, gentle and uniform stroke for each side. A well hard-
ened film should dry of its own accord in 20 to SO minutes after being
suspended. For quick drying an electric fan may be used, provided one is
sure the fan will not direct a stream of dust onto the film. Dust particles
hurled at the delicate gelatine surface will become imbedded in it beyond
hope of removal. It is therefore preferable that the current of air strike
the uncoated celluloid back side of the film.

Soaking a Film Before Development

Unless the exposed film is old and brittle it should not be soaked in
water before development. There seems to be no advantage in pre-
soaking a film to be developed. It would be just one unnecessary opera-
tion. The old contention in favor of such a procedure was that it pre-
vented formation of air bells and enabled the developer to start work
more quickly and uniformly by presoftening the emulsion. Air bells are
successfully eliminated by agitating the developer as soon as it is poured
into the tank; while the developer needs no presoftening of the emulsion to
start its uniform action which is to continue for some twenty minutes
anyhow.

It is one of the features of the technique offered here to develop a
Leica film with the utmost simplicity and effectiveness, with complete elim-
ination of all steps of doubtful value.

Step by Step Developing Procedure

To develop a roll of Leica film proceed as follows :

Step 1. In total darkness wind film onto the spool of the developing
tank, emulsion side in (facing center of reel). To do so,
do not pull the film out of the closed or partly opened
magazine. Open the magazine, take the spool out and hold
it in the palm of the hand while rewinding it onto the reel
of the developing tank. Be sure to close tank carefully
and securely before turning on light.

124

Film Development

Step 2. Cool developer to exact temperature required for given
developer. While cooling developer, prepare short-stop
bath and the hypo. Short-stop bath should be about the
temperature of the developer. Hypo not less than 65°F.
(18°C.) or more than 70°F. (21°C.).

Step 3. Pour developer in steady stream into developing tank.
Directly after filling tank, observe time on clock and start
agitating developer. Agitate for about one minute, not
vigorously but steadily to prevent formation of air bells.
Agitate every three to five minutes thereafter.

Step 4. One-half minute before expiration of full time called for
by developing formula, start pouring out developer from
the tank (pour into original storing container, unless de-
veloper life is exhausted) . Shake all developer carefully
out of tank.

Step 5. Without rinsing, pour the short-stop bath into tank in a
steady stream. Observe time on clock and start agitating
for about one minute. Leave short-stop in tank for five
minutes, agitating occasionally. Pour it off at expiration
of time. The short-stop should be used once only.

Step 6. Pour in hypo without rinsing tank. Start agitating
directly after tank is filled with hypo and continue every
two or three minutes. Fresh hypo should remain in tank
for 10 minutes. At the end of 10 minutes, pour off hypo.
Hypo should not be used for fixing film more than twice
(preferably once). It can then be used for fixing out
papers.

Step 7. After pouring out hypo, fill the tank with running water.
Adjust it to a temperature of between 65°F. (18°C.) and
70°F. (21°C). Water colder than 65°F. will not wash
the film properly; warmer than 70°F. it is likely to soften
the film. After filling tank with water, agitate it briefly
but vigorously, pour oui water and put tank under tap,
letting the water run down in a steady stream for about
twenty to thirty minutes.

Step 8. Remove film from tank. Hang it by film clips in a cool,
dry, dust-free place and wipe off excess water gently from
both surfaces of film by means of Viscose Sponge. The
sponge should be wet, but thoroughly squeezed out. When
wiping emulsion side only the gentlest pressure should be

125

exerted to prevent scratching. The celluloid side of the
film should be dried thoroughly with slightly more pres-
sure. Film will dry normally in twenty to thirty minutes,
but it is best to let it hang for about three times the length
of time it requires for the film to become concave with
respect to the emulsion side.

Step 9. Boll film carefully, emulsion side in, and store it in a dry,
dust-free, clean box. A small rubber band slipped over the
roll will prevent film from scratching.

Step 10. It is best not to put the film into an enlarger for from six
to twelve hours after it has dried out. Objectionable
Newton rings will form if " green " film is placed in the
enlarger.

Complete Procedure for REVERSAL of Agfa Superpan Reversible Film

Keversible Superpan should be handled in total darkness. It can, however,
be desensitized in a 1:2000 Pinakryptol Green Solution for two minutes,
and then handled in bright green light such as the Agfa #103 green safe-
light with a 25 W. bulb.

The reversal procedure is divided into six basic operations, which are inter-
spersed with appropriate periods of washing in running water.

1. DEVELOPMENT OF THE NEGATIVE IMAGE
First Developer.

Avoirdupois Metric

Water (125° F. or 52° C.) 24 ounces 750.0 cc

Metpl 30 grains 2.0 grams

Sodium Sulphite 1 ounce 30.0 grams

Hydroquinone 180 grains 12.0 grams

Potassium Bromide 120 grains 8.0 grams

Sodium Hydroxide 265 grains 18.0 grams

Potassium Sulphocyanate 75 grains 5.0 grams

Cold Water to make 32 ounces 1000.0 cc

Develop normally exposed film for 6 minutes at 65° F. or 18° C. with constant
though not too rapid agitation. Do not use this developer more than once for
consistently good results.

Wash film in running water for 10 minutes.

The accuracy of the first development and the thoroughness of washing following
it are the two most important steps in the entire procedure.

126

Film Reversal

2. REVERSAL
Reversal Bath (Bleach)

Water to make 32 ounces 1000.0 cc

Potassium Bichromate 75 grains 5.0 grams

Sulphuric Acid (Concentrated) 1.3 drams 5.0 cc

Add Sulphuric acid last, pouring it slowly while stirring-.

Agfacolor Plate Reversing Salts put up in tubes, ready to be dissolved in 18

ounces of water may be substituted for above reversal bath.

After the film has remained in the Reversal Bath for at least 2 minutes,
white light may be turned on in the darkroom, and the remainder of the
procedure may be conducted in white light.

Carry on reversal until both the negative image and the anti-halation under-
coating are dissolved leaving only the undeveloped silver haloid. This requires
about 5 minutes.

"Wash film in running water for 5 minutes.

3. CLEARING
Clearing Bath

Water to make 32 ounces 1000.0 cc

Sodium Sulphite (dessicated) 1 2/3 ounces 50.0 grams

Clear in above solution for 5 minutes. Yellow stain is gradually removed and
the emulsion assumes a clear white color.

Wash in running water for 2 minutes.

4. RE-EXPOSURE TO LIGHT

Thoroughly expose film to white light of a 200 watt bulb or of a Photoflood bulb
(either bulb should be placed in a reflector). Hold film about 6 feet away from
light, rotating it so that its entire surface, both front and back, Is thoroughly exposed.
Exposure required: 2-3 minutes. Direct sunlight should not be used. Film should not
be held too closely to light source to avoid injury to emulsion from heat.

5. REDEVELOPMENT

Second Developer

Water (at 125° F. or 52° C.) 24 ounces 750.0 cc

MetoJ 30 grains 2.0 grams

Sodium Sulphite (dessicated) 370 grains 25.0 grams

Hydroquinone 60 grains 4.0 grams

Sodium Carbonate (monohydrated) . . . 295 grains 20.0 grams

Potassium Bromide 30 grains 2.0 grams

Cold water to make 32 ounces 1000.0 cc

Develop until image has become thoroughly blackened, which requires about
5 minutes.

Rinse in running water for 3-5 minutes.

127

6. FIXING

Fix for five minutes in regular acid hardening fixing hypo bath (p. 123).

Wash in running water for 10-15 minutes.

Wipe off surface water gently with the aid of viscose sponge.

Hang up film to dry.

All solutions and the running water should be maintained throughout the
procedure at 65° F. or 18° C. Utmost cleanliness is required for success-
ful results. Avoid contamination of solutions through carrying one into
another.

General Suggestions

Utmost cleanliness should be observed throughout processing of Leica
negatives.

Use only the best and purest chemicals, and once a brand is adopted
continue to use it for uniform results.

Observe greatest accuracy in weighing and measuring chemicals.

Never permit fingers to come in contact with emulsion side of film
either before or after developing.

Never handle film except by its edges.

If film becomes soiled, wipe it carefully with a soft chamois skin
dipped in a suitable film cleaner (see page 130).

Apron of Correx tank should be removed when not in use, and kept
suspended by one or both its ends.

Films should be kept as far away as possible from heat, radiators, hot
water pipes, etc. It should be remembered that most of our negative ma-
terial is nitrate stock and highly inflammable. Therefore films should be
kept in a well ventilated cool dark place, away from open flame.

Developing and handling of Leica negatives should not be turned into
an obsession, but should be considered as only one of the factors which
contributes towards the final picture.

Reticulation

Reticulation is a peculiar phenomenon occurring on films, and in the
case of Leica films it may actually ruin an otherwise perfect negative.
It is due to local strains in the gelatine which may be caused by a sudden
change in temperature of solutions, or atmospheric conditions. It occurs
in different degrees, from an extremely mild form barely distinguishable
by the eye, to a very severe form. Reticulation looks like miniature ele-
phant skin shrivelled into a labyrinth-like pattern. In its severest form
it produces actual tiny cracks in the emulsion; the accompanying illustra-
tion shows this condition.

Reticulation can happen at any point during processing of film, in-
cluding pre-soaking, during development, or at the point of change from
developer to hypo. It can even occur while the finished film is drying.

To minimize the danger of reticulation, the pre-soaking of the film,
and its washing between solutions should be entirely eliminated. The use
of the short-stop as an intermediate bath between the developer and hypo
cannot be recommended strongly enough. The chrome alum and sodium
bisulphite short-stop has a beneficial effect upon the film by its gentle
hardening and slightly acid action as a transition from the alkaline de-
veloper to the highly acid hardening fixing bath. It is believed that the
short-stop carried over in small quantities into the hypo bath corrects
the acidity of the latter to the point where it will not cause reticulation*

128

Film Development

Fig. 87 Reticulation, mild Fig. 88 Reticulation, acute—

(Anonymous!) cracks in emulsion

(Anonymous ! )
Newton Rings

Another source of considerable annoyance are the so-called Newton
rings. These are irregular spots of all colors of the spectrum appearing
on the surface of the enlarging paper while the negative is in the enlarger
for printing. In appearance these Newton rings suggest those charac-

Fig. 89 Masking plate for elimination of Newton Rings, actual size for
tracing

129

texistic, rather pretty, patterns which oil forms on water. While pretty
to look at, Newton rings are a decided nuisance for they will ruin any
print, and are hard to eliminate.

They occur particularly on "green" film, that is, film that has just
been dried but still contains moisture. For this reason it is recommended
that films not be put into the enlarger for six to twelve hours after drying.

Newton rings are actually caused by the condenser of the enlarger
not being in perfect contact with the entire back of the film, but merely
touching it at several points, indicating that the film is not in a true plane.

Of most remedies suggested for correction of this annoying condition
the one providing a special mask or spacer, as shown in the cut which is
a full size tracing, is the most practical. This masking plate can be made
from a thoroughly fogged, developed and fixed out piece of cut film, with
the aid of a sharp razor blade. The regular masking negative carrying
plate is taken out of the enlarger, the film placed over it as usual emulsion
side down, and the special mask placed over the negative; the entire as-
sembly is then slipped into the enlarger and from this point the procedure
is Carried on as usual.

Film Cleaner

Film that is dusty, dirty, shows finger marks, lint, etc., should be
carefully cleaned before placing it in the enlarger.

An excellent all-around film cleaner is easily prepared as follows:
Ethyl Alcohol (pure grain alcohol) ... 85% (or parts)

Methyl Alcohol (wood alcohol) 10% (or parts)

Strong Ammonia 5% (or parts)

This cleaner is not "dry", as is carbon tetrachloride and similar cleaners.
Because this cleaner is "wet", it does not charge the film electrically, thus
leaving it without the usual tendency to attract lint and dust from the
air. This cleaner should be applied to both surfaces of the film with a
clean, lintless fine linen cloth, soft chamois or lens tissue.

Reducing or Intensifying Leica Negatives

These two processes are, to say the least, dangerous for miniature
camera work, and their use is definitely discouraged. Either of these pro-
cesses increases the grain considerably and destroys definition. However,
for those who wish to save a valuable negative, the two formulas most
suitable for miniature camera work are offered:

E.K. FORMULA R-5— PROPORTIONAL REDUCER

Stock Solution A

Avoirdupois Metric

Water 32 ounces 1.0 liter

Potassium Permanganate 4 grains 0.3 gram

Sulphuric Acid (10% solution) Yz ounce ' I6J3~ccT

Stock Solution B

Water f ..."".; 77 "96" ounces SrOHDSers

Ammonium Persulphate 3 ounces 90.0 grams

For use, take one part of A to three parts of B. When sufficient reduction is
secured the negative should be cleared in a 1% solution of sodium bisulphite.
Wash the negative thoroughly before dryinjr.

130

Film Intensification

E.K. FORMULA IN-5— SILVER INTENSIFIER

For 35mm Negative and Positive Films

The following formula is the only intensifier known that will not
change the color of the image on positive film on projection. It gives
proportional intensification and is easily controlled by varying the time of
treatment. The formula is equally suitable for positive and negative film.

*Stock Solution No. 1

Avoirdupois

Silver Nitrate 2 ounces

Distilled water to make 32 ounces

* Store in a brown bottle.

Stock Solution No. 2
Sodium Sulphite, desiccated. 2

Water to make.

ounces
ounces

Stock Solution No. 3

Hypo 3 1/2 ounces

Water to make 32 ounces

Metric
60.0 grams

1.0 liter

60.0 grams
1.0 liter

105.0 grams
1.0 liter

Stock Solution No. 4

Sodium Sulphite, desiccated l/2 ounce 15.0 grams

Metol 350 grains 24.0 grams

Water to make 96 ounces 3.0 liters

Prepare the intensifier solution for use as follows : Slowly add 1 part of solu-
tion No. 2 to 1 part of solution No. 1, shaking or stirring to obtain thorough
mixing. The white precipitate which appears is then dissolved by the addition
of 1 part of solution No. 3. Allow the resulting solution to stand a few min-
utes until clear. Then add, with stirring, 3 parts of solution No. 4. The
intensifier is then ready for use and the film should be treated immediately.
The degree of intensification obtained depends upon the time of treatment
which should not exceed 25 minutes. After intensification, immerse the film
for 2 minutes with agitation in a plain 30% hypo solution. Then wash thor-
oughly.

Storage and Preservation of Films

This matter is again a question of personal preference. The writer
knows of as many storing and filing systems as he knows Leica workers.
There are transparent cellophane envelopes in book or box form holding
strips of from three to eight negatives. There are books with flaps of
transparent paper and books with pockets. There are filing cabinets and
chests of endless variety.

Personally, the writer prefers to preserve, store and file Leica nega-
tives in uncut lengths, in rolls firmly but not tightly wound. A small rub-
ber band (about Vzn diameter) is slipped around the roll before placing
it in a steel box divided into small sections of twenty-five to a box. Each
roll is given a number and a brief description of the entire roll marked
under the corresponding number on ihe inside lid of the box. Each box
is marked with an alphabet number and a record kept in a loose leaf
scrap book into which contact prints from every roll are pasted.

The Negative Viewer and Marker is Con-
venient for Examining Completed Films

131

132

tl^E

JOHN N. HARMAN, JR. CHAPTER 5

Probably 'everyone who (has ever made a Leica shot and
" blown it up" to a good sized enlargement has wished for an
opportunity to do a bit of retouching on minor parts of the nega-
tive. But a microscopic eye is needed for work as exacting as this
and retouching and spotting have as a result been relegated to the
final print.

Many a cynical megacamist has seized this apparent fault as
the clinching point in his arguments against "postage stamp'7
negatives. And this with little reason, for there are three ways
by which Leica photographs may be conveniently put into the form
of enlarged negatives for retouching before the final print or en-
largement is made.

Retouching, however, is not the only advantage offered by the
use of enlarged negatives — for they come in handy in many ways.
Whenever several enlargements requiring dodging or projection
control are desired to be made identical with one another, the use
of an enlarged negative not only simplifies the procedure and cuts
the over-all working time, but it insures the uniformity of the final
prints. All the dodging and retouching may, for example, be done
upon one master enlarged negative of from 4x5 to 8 x 10 inches
in size, and all prints of any size may be contact printed, enlarged,
or reduced from this with unvarying results. The contrast of ori-
ginals that are too dense or too flat may also be Improved in the
preparation of the enlarged negative. Furthermore, enlarged nega-
tives offer an excellent medium for the combination of parts of
different negatives when, as is sometimes the case, the final print
is built of several separate images.

There are three methods which may be used to obtain good
enlarged negatives without excessive time or trouble in processing.

The first involves the use of a new and .singular photographic
m^'erial, "Direct Copy Film". This unusual film produces a
negative directly from a negative — although it is processed in a
manner no different than that regularly used for chloride printing
paper.

133

The second method is based upon the use of a reversible film
for the original exposure in the Leica. Upon special development,
this reversible film produces a positive (normally used for pro-
jection purposes) which is then enlarged on a process or commercial
film to give the enlarged negative.

The third method embraces the preparation of an intermediate
film positive from which the enlarged negative is made. This is
naturally the longest process in point of time but it is well known
and will do the trick admirably if the special films required for
either of the first two methods are not obtained.

Direct Copy Film is a new material which is being manufactured by
the Agfa Ansco Corporation of Binghamton, N. Y. The emulsion of this
remarkable film has properties by means of which it can produce in one
single exposure and development a negative from a negative (or for that
matter, a positive from a positive). The emulsion of the film is treated
during manufacture so that when developed without any exposure what-
soever, a maximum density of opaque silver is produced. However, for
every increasing amount of exposure the film shows a corresponding
increase in transparency after development. Thus, light parts of an ori-
ginal are duplicated by transparent portions of the copy film and shadow
regions of the original are represented with equal accuracy. Aside from
this unusual characteristic the emulsion of Direct Copy Film resembles
a chloride printing paper in color sensitivity, required exposure, and gen-
eral handling and processing in the darkroom. Because Direct Copy Film
has an extremely fine-grained emulsion no additional graininess is pro-
duced in the final enlargement by this method.

Because of its peculiar properties, Direct Copy Film makes the prep-
aration of enlarged negatives a rapid and simple procedure. The only
operations requiring special mention are those of exposure and develop-
ment. Fixation and washing are done in the conventional manner.

Since Direct Copy Film has approximately the same speed as the
standard soft grades of contact printing paper, Leica negatives may be
enlarged onto it without unduly long exposures when a photoflood bulb is
used in the enlarger. A small strip of chloride printing paper such as
Convira may be used in making a preliminary test exposure, and the cor-
rect printing time determined from the test exposure. The piece of Direct
Copy Film should be mounted on the enlarging easel with the emulsion
side up. The Leica negative to be enlarged should be inserted in the en-
larger, not in the usual way, but with the emulsion side facing upward
instead of downward. This will give a reversed (from left to right) image
on the easel and a correct image in the final print. The density of the
enlarged negative should be controlled by adjusting the exposure and not
by modification of the developing time. Thin copy negatives indicate
over-exposure, while an enlarged negative that is too dense is the result
of under-exposure. Amber or bright orange light may be used in the
darkroom.

134

Enlarged Negatives

Development of the enlarged negative on Direct Copy Film can be
carried out in any soft-working film developer, but the two following
formulas are recommended for best results.

For Normal Gradation on Direct Copy Film

Avoirdupois Metric

Water to make 32 ounces 1.0 liter

Metol 23 grains 1.5 grams

Sodium Sulphite, anhydrous ...... 2 oz. 290 gr. 80.0 grams

Hydroquinone 45 grains 3.0 grams

Borax 45 grains 3.0 grams

Potassium Bromide • • 8 grains 0.5 grams

Use without dilution. Develop 12 to 20 minutes at 5° F. (18° C.)-

For Moderate Brilliance on Direct Copy Film

Avoirdupois Metric

Water (lukewarm) 32 ounces 1.0 liter

Metol 90 grains 6.0 grams

Sodium Sulphite, anhydrous 6 ounces 180.0 grams

Sodium Bisulphite 60 grains 4.0 grams

Hydroquinone 180 grains 12.0 grams

Sodium Carbonate, monohydrated . 360 grains 24.0 grams

Potassium Bromide 48 grains 3.2 grams

Add cold water to make 1 gal. 4.0 liters

Use without dilution. Develop 8 to 10 minutes at 65°F. (18° C.).

As mentioned above, variations in results should be controlled more
by adjustment of exposure rather than by modification of developing
time. Best results will be obtained by keeping within the times recom-
mended for each developer. Stains will be avoided by the use of a con-
ventional acid short stop bath between development and fixation.

Enlarged Negatives from Reversible Film Originals

The second method of preparing enlarged negatives relies upon the
use of a reversible film in the Leica for the original exposure. This film
is developed by a reversal process to a positive, usually for projection
purposes. A film of this kind, prepared especially for the Leica, is made
by the Agfa Ansco Corporation of Binghamton, N. Y., and is sold under
the name of Superpan Reversible. It is a high speed, panchromatic
material which may be compared to the supersensitive type in group 1
(see pages 101, 104). Because it is a reversal film it gives positives
which have an exceptional fineness of grain — a noteworthy point for all
miniature-camera work. The positive resulting from the processing of
the Superpan Reversible Film can be easily enlarged onto a piece of
Commercial, Commercial Ortho or Process Cut Film and developed in a
standard negative film developer. The exposure required by Process Film
will be about the same as that needed for the faster grades of Bromide
enlarging paper, while Commercial and Commercial Ortho Film will
require about one-tenth as much exposure.

135

The processing of the reversible film original will be done at a nom-
inal charge by the film manufacturer but it can be carried out satisfactor-
ily in about two hours by the procedure outlined in detail on page 126
of this volume.

Enlarged Negatives by the Positive-Negative Process

The third method by which enlarged negatives may be made from
Leka originals requires the preparation of an intermediate positive film.
This may be made, of course, by contact printing onto 35mm. positive
film stock and proceeding as with the reversible film positive. However,
greater convenience is undoubtedly afforded by the preparation of the
intermediate film positive in an enlarged form. This is easily done by
enlarging the original Leica negative onto a sheet of Process or Commer-
cial Film instead of the usual bromide paper. Development can be carried
out in a conventional negative film developer such as the following:

Avoirdupois Metric

Water (lukewarm) 32 ounces 1 liter

Metol 90 grains 6 grams

Sodium Sulphite, anhydrous 6 ounces 180 grams

Sodium Bisulphite 60 grains 4 grams

Hydroquinone 180 grains 12 grams

Sodium Carbonate, monohydrated . . 360 grains 24 grams

Potassium Bromide 48 grains 3.2 grams

Add cold water to make 1 gal. 4 liters

TRAY DEVELOPMENT: Use full strength. Normal devel-
opment time, 5 to 7 minutes at 65°F.

TANK DEVELOPMENT: Dilute one part above developer to
one part water. Normal development time, 12 to 14 minutes at
65°F.

This enlarged positive film when fixed, washed and dried can then be
contact printed or enlarged onto another piece of Process or Commercial
Film to produce the final enlarged negative. Retouching and dodging
can, of course, be done at either of the two intermediate steps — inter-
mediate positive, or final enlarged negative. If Process Film is used for
both intermediate positive and final master negative, developing time
should be decreased to avoid results of excessive contrast.

EDITOR'S NOTE: For finer gradation, softness and minute details
expected of pictorial work, it may be found that substitution of the posi-
tive Process or Commercial film, suggested by the author, by a softer film
may be more effective. Reference is made to the type of film offered by
orthochromatic emulsions such as Eastman Portrait or Safety Ortho films,
Agfa Plenachrome or Defender Pentagon. These films are more sensitive
to light in general and a shorter exposure is required than for the positive
film. The Safelight, of course, would need to be changed from yellow to
ruby, according to recommendations contained in each package of film.
Otherwise, the procedure is not different from that outlined by the author.

136

WILLARD D. MORGAN CHAPTER 6

A photographic darkroom can be the source of many enjoyable
hours. Here is a place where you can try out some of those new
photographic ideas of yours, make your exhibition enlargements, try
out the latest developing formula, make photo-montages, lantern
slides, develop color film, and experiment with various enlarging
papers. As you complete your darkroom it will quickly become the
meeting place for your friends who have similar interests. After a
hectic day at the office or some other occupation the evening hours
in your darkroom will be one of the most enjoyable relaxations you
can experience.

Make the darkroom a model of convenience, cleanliness, and neat-
ness. If you cannot find space for a separate room for your work
don7t worry but fix up the kitchen sink for your developing and en-
larging equipment. Dark shades over the windows will exclude all
light, and the darkroom safety light may be easily installed over
the sink. If the kitchen is not convenient explore the bathroom and
confiscate one corner for your equipment. A wide board over the
bathtub will hold several trays, while the bathtub and sink may be
used for washing the prints or films. There are thousands of if bath-
tub finishers" located in every section of the country who are doing
excellent photographic work. The writer belonged to this fraternity
of "bathtub finishers'' for many years before he had an opportunity
to enjoy the thrills of having a separate darkroom completely
equipped for his work.

If you happen to be living in a small apartment and wonder
how you can solve the darkroom situation try converting the kitchen-
ette into a darkroomette. Such a transformation has been cleverly
done by John T. Moss, Jr. of New York. The accompanying photo-
graph will give a complete plan of Mr. Moss's darkroomette. Note
that the folding doors may be closed or opened as required. The
refrigerator can be used for keeping solutions cool, or it may be a
source of ice cubes when required. It is surprising how small a space

137

can be utilized for doing all one's developing and enlarging work,
so don't let the space problem worry you when yon set up a place to
do your finishing work. J. Harlan Davis of Mt Vernon, Ohio has
solved his space problem by constructing a * 'folding darkroom'5
right in his library. He has constructed a wall cabinet which holds
all his equipment, and the door swings down to make the work table.

Fig. 92 "Darkroomette"
of John T. Moss/ Jr., util-
izing facilities of the mod-
ern kitchenette

A Model Darkroom

In order that we may obtain a complete picture of what an
amateur darkroom should look like let's take the model darkroom
recently constructed by Lee Parsons Davis of New Bochelle, N. Y.
The accompanying photographs and drawings will give you complete
information, even better than any long detailed descriptions. Mr.
Parsons based his plans upon a similar darkroom constructed by
Clifford H. Beegle of Beaver Falls, Pa.

The inside dimensions of Mr. Parsons' darkroom are seven feet
by six feet. Although this space may at first seem small it is sur-
prising how much room there is to work and also how much space
there is for storing equipment and supplies. The secret of this space
utilization is that there are many storage drawers, and several shelves
for chemical storage. Space has been made for print drying racks,

138

Leica Darkroom

ferrotype tins, and a large sink five feet long by sixteen inches wide
and one foot deep. The sink is constructed of California white pine
1*4 inches thick. The side and end boards are 12^ inches wide, and
the bottom is one wide board. These boards were grooved to fit at
a planing mill, and set together without glue or nails, then bolted
on the ends and bottom.

There are three faucets over the sink, two of which are combina-
tion faucets which permit the proper temperature regulation of the
water. One of the faucets has a small under valve which permits an
outlet for tray washing of prints as shown in the accompanying illus-
tration. A removable drainboard for the sink provides for additional
working space when required. The 11 by 14 inch developing trays
will fit across the sink while the space below can be used for a larger
washing tray. Plenty of electrical connections, safety lights, as well
as the regular white lights are provided.

Finally, and one of the most important points to consider in the
darkroom is the ventilation. A fresh air inlet has been provided for
through the door of the darkroom, while the foul air is sucked out
through a light-tight duct by an electric fan. This permits constant
circulation of air, and when two or three people are working in the
darkroom at one time there is always plenty of good clean air.

Fig. 93 Interior of photographic
laboratory of Lee Parsons Davis.

Fig. 94 Outside of Mr. Davis' pho-
tographic laboratory showing posi-
tion of exhaust fan.
Note light trap ventilator on door.

139

Fig. 95 Elevation facing work bench showing enlarging table, cabinets
and cross-section of sink

Key to drawings (figures 95, 96, 97) :

No.
No.
No.
No.
No.
No.
No.
No.
No.
No. 10
No. 11
No. 12
No. 13
No. 14
No. 15
No. 16
No. 17
No. IS
No. 19
No. 20
No. 21
No. 22
No. 23
No. 24
No. 25
No. 26
No. 27
No. 28

No. 29
No. 30

Work tench and cabinet for print drying racks

Sink — lead lined

Wratten safe light, series No. 3, 40-watt Mazda bulb

Safe lights

Electric convenience outlets

Electric outlet for enlarger

Electric bright light

Electric exhaust fan

Fresh air inlet (light trap)

Foul air discharge duet

Cold water faucet

Combination hot and cold water faucet

Variable overflow drain pipe

Removable drain board

Sliding enameled developing trays

Towel rack

Light-tight door gasket

Air thermometer

Coat hook

Stool

Light-tight blind for exterior window

Storage shelf for chemicals, etc.

Storage space for solutions

Trimming board and cutter

Tray storage racks

Storage space

Equipment and supply drawers — full depth of work bench

Bench top and back b'oard covered with acid and alkali proof Micarta 1/16" thick

witn chromrum trim

Foul air outlet grille

Proposed recessed cabinet for books and film storage

140

(2)

Fig. 96 Elevation showing sink, exhaust fan, safe lights, drying racks, etc.

Fig. 97 Plan of Lee Parsons Davis' model darkroom.

Stocking the Complete Laboratory

Naturally one's darkroom equipment and supplies will be determined
by individual tastes and requirements. Here is a list to consider when
stocking your laboratory with everything- but the "kitchen stove".

Developing1 tanks for film . . . developing trays for paper enlarge-
ments . . . enlarging equipment . . . film and glass slide contact printers
. . . illuminating control rheostat for use with photoflood bulb in en-
larger . . . paper cutter . . . safety lights for paper and films . . .
chemicals and chemical weighing scale . . . electric agitator for film
developing tank . . . thermometer . . . cotton and viscose sponges
. . . supply of bottles for keeping solutions . . . supply of beakers and
graduates for mixing and measuring solutions . . . small electric stove
^for heating solutions . . . metal clips for hanging film to dry . . . de-
veloping glass drum for color films or reversing other films . . . supply
of enlarging paper . . . filing boxes for negatives which must be kept
free from dust at all times . . . and finally a small corkboard mounted
on the wall for tacking up formulas and special data which is often re-
ferred to such as weight conversion tables, developing times at various
temperatures, etc.

A Two Room Laboratory

Now let's study still another darkroom or laboratory which is a
little more elaborate and has the double room feature with a small
separate nook for the chemical mixing department. This darkroom
was designed by Clarence Slifer of Hollywood, California and de-
scribed in the August 1934: issue of the American Cinematographer.
Mr. Slifer describes his laboratory as follows :

In keeping with the progressiveness that is so apparent in Miniature
Photography, herewith is presented a plan of a model laboratory. This
room in which photographic processing is carried on, is not called a dark-
room, simply because that word is a misnomer. It is not dark, for at all
times, with the exceptions of when loading magazines or developing tanks,
there is an abundance of light: properly filtered light for printing and
daylight for other operations.

Removed is the stigma that the word darkroom has implied. This
model laboratory is not a poorly ventilated closet, under the cellar stairs,
but is a room planned for comfort, convenience, and practicability. All of
which are conducive to better photographic work and the full enjoyment
of miniature photography.

From the plan, it will be noticed the room is divided into two main
divisions; the laboratory proper and the study. The laboratory, to take
care of all photographic work from glossy prints to the advanced pic-
torial processes. The study, to serve as a place for working out pho-
tographic problems or as a place where you may argue with friends about
the gammas, the paraphenylenes, and the reticulations of photography,
without having your sanity questioned by other members of the household
or being relegated to that esteemed position now held by butterfly-chasing
professors.

The essential features of the model laboratory are:

1. A shallow wooden sink provided with removable slats for tray sup-
ports. Its six-foot length easily handles three trays UTD to 36"*20" in

142

Leica Darkroom

size. Swing faucets practically "cover" the entire sink. Above the
sink are shelves for stock solutions, etc. Below the sink, are racks
for trays, box for waste and space for miscellaneous equipment. In
the wall, above the right end or the sink, is a light-tight ventilator.
This ventilator withdraws all hypo or chemical fumes arising from
developing or toning prints. Also at this end of the sink, is a light
fixture containing a day light bulb. The light from this fixture is
concentrated down upon the hypo or toning tray, and is actuated by a
foot switch. This permits examining prints for tone or contrast with-
out drying the hands. The safe-light used for observing the develop-
ing of prints, has two degrees of brilliance: dim and bright. The
bright light is controlled by a foot switch and is used only for limited
periods of print examination. For cleanliness, liquid soap and paper
towels are a part of the sink equipment.

2. A film ^ developing bench especially equipped for miniature negative
developing. The importance of agitation in small film processing- is
recognized by the inclusion of an electric agitation machine in the
laboratory equipment. Also provided is a negative viewing box (a
white light behind opal glass). Affixed to the glass are gamma films
of different densities for use in judging the progress of development.
An ice chest for cooling solutions may be placed under the bench.

3. A print washing machine preferably of the Kodak rotating type. This
provides a quick, efficient, and thorough means of washing prints with
little handling.

Fig. 98 Plan of two
room laboratory designed
by Clarence Slifer

•/CAlfr 1PODJ

143

4. A drain-board for prints after they have been removed from the
washer.

5. A holder for paper towels and a shelf for the radio (the companion
in the laboratory). Indicated here, is a stool, as much printing may
he carried on while seated.

6. A double, indirect safe-light for general room illumination.

7. A long cabinet of an exaggerated desk-like appearance, with shelf
or cabinet space above. Underneath the left end is a set of drawers
for keeping Bromoil brushes, paints, and other materials. Space is
provided for leg-room when seated before the portion of the bench
at the window. Here is an ideal place to work upon Bromoils, spot
or color prints, retouch enlarged negatives, etc. Underneath the right
end of the bench, are frames with stretched cloth-net for laying prints
upon, to dry.

8. A sliding light-tight shutter for the window.

9. A cabinet-bench for a miniature negative enlarger of the Leitz Foco-
mat or Valpy type. The enlarger is controlled by a foot switch, thus
leaving both hands free for "dodging". This freedom is further en-
hanced by the use of a metronome for timing prints audibly, during
difficult exposures. At other times a large electric clock serves the
purpose. On the wall, back of the enlarger, is an Illumination Control
Rheostat for use with a Photo-flood lamp, when enlarging upon chlo-
ride (contact) papers. Light-tight drawers are in the cabinet, for the
storage of photographic paper. To the left of the enlarger, is a print
trimmer. To facilitate print trimming, the edge of the print trimmer
is illuminated by a light, sunk in the cabinet.

10. An Il"xl4" contact printing machine, which is used for printing en-
larged negatives and also strips of Leica film, for proofs.

11. A film loading and negative filing desk.

12 Chemical closet, for chemical storage and mixing. In the lower part
of the cabinet, is a bin for hypo crystals and a fixture for supporting
a five-gallon bottle of distilled water. Due to its location, chemical
dust in the laboratory is eliminated.

13. Light-tight entry to the laboratory, affording easy access and ventila-
tion. The partitions fold back, whenever it is desirable.

14. Dry mounting press, for mounting photographs.

15. Bookshelves, for those indispensable photographic books and maga-
zines.

16. A light-tight film drying cabinet, six feet high. Air is drawn in,
through silk screens, from the study, thus minimizing the nuisance of
dust. The cabinet may also be used for drying hyper-sensitized film.

17. A cabinet for camera equipment. Upon this cabinet is an easel for
holding prints to be admired or glared at. A conventional, picture-
illumination fixture is used for light.

18. A Bromoil transfer press and a cabinet for card stock, etc.

19. Desk-like drawing table with long fixture for diffused light above.

20. Long, comfortable window seat.

The plan of this model laboratory is based upon the knowledge gainec
from a number of years' experience in many photographic "darkrooms"
So turn back and study the plan over, for perhaps you may find some ideas
for your Ideal Laboratory for Leica Photography.

144

PRINTING

WILLARD D. MORGAN CHAPTER 7

After the Leica negative has been made the next step is to have
it printed, either by contact upon paper or film, or by direct enlarge-
ment. The choice in printing really depends upon our individual
requirements. Some prefer to make paper contact prints of all their
negatives for reference purposes, while others would rather make
enlargements direct. In order to reproduce the finest qualities in a
Leica negative it is necessary to either make positive film or glass
slides for projection upon a screen or to make enlargements upon
some of the various printing papers now available. "We will discuss
the methods for enlarging first.

Making positive prints from Leica negatives offers many distinct
advantages :

1. There is the choice of many fine enlarging- papers which may be secured
in various surfaces and grades of contrast. The chapter on enlarging
papers will give complete information on this point.

2. Enlargements may be shaded or dodged during- the printing in order to
emphasize or hold back any portion of the picture. For example an
overexposed sky may be printed longer than the underexposed fore-
ground.

3. The unattractive or disturbing parts of a negative may easily be omitted
to improve the composition of the finished picture.

4. The enlarging easel and the enlarger housing* may be tilted for correct-
ing* the perspective in a picture. This feature is especially valuable when
enlarging architectural pictures which have been taken close to the
subject with the camera pointed slightly upward or at a sharp angle.

5. The slow printing contact or chloride papers can be used when a photo-
flood bulb is placed in the enlarger.

6. Enlarging screens, gauze, special effect filters, and other accessories
may also be used with the enlarger for securing special effects in en-
largements to please the various individual tastes.

7. The Leica enlargement of post card size or larg-er produces a picture
which can easily be studied by anyone.

Selecting the Enlarging Equipment

Before the actual enlargements can be made it is necessary to
select the proper enlarging equipment. A good enlarger will last a
lifetime. By actually enlarging your own negatives you will learn

many things about your pictures. You will have a keener sense of
the proper composition, a better judging of correct exposures, im-
proper focusing \vill show up instantly, and even when you are making
your original picture you may have in mind certain enlarging papers
for the subjects taken. So in order to gain these advantages let's
become more familiar with the actual working equipment available.

The Valoy Enlarger

The present Valoy enlarger is actually the outgrowth of the former
Filoy and F^lab enlargers. While these latter enlargers are still producing
excellent eJargemeiat! for those who still own them, the present Valoy
enlarger was constructed to give a few additional conveniences in handling
the negatives. This enlarger may be described as follows:
1 Baseboard, 15% x 18 inches in size, for holding the paper easel and
the metal upright bar which supports the enlarger lamp housing.

2. Upright metal bar, l£ inches in diameter, available in 80cm and 120cm
lengths. Electric connecting wire passes through the center of the
metal upright. At the base of the upright iS> a grounding connection
marked "E" for attaching a ground wire if desired.

3. Lamp housing supported by an extension arm which clamps around
the metal upright bar.

4 Adjustable lamp base for centering and otherwise moving the enlarging
bulb into the best position to give an even illumination over the entire
negative area.

5. Removable condenser with adjusting lever for clamping Leica negative
into position for enlarging.

6 Space for accommodating various masks for single frame, Leica double
frame, 3 x 4cm, and 4 x 4cm negatives. Hinged glass negative holders
also available for use with single negatives which have been cut from
the regular rolls.

7. Focusing lens mount will accommodate the ^various Leica lenses. The
50mni lenses are recommended for use in this enlarger.

8. The condenser may be removed for cleaning by turning the clamping
ring inside of the lamp housing, removing the spring, and then lifting
out the condenser. It is a good plan to remove this condenser fre-
quently and carefully clean the surface with lens tissue or a clean
linen.

9. An Intermediate ventilating ring is recommended for use with the
Valoy enlarger when a photoflood bulb is used.

10. A small snap switch is attached to the baseboard of the enlarger for
making the exposures.

The Focomat Enlarger

The Focomat Enlarger is ver7 similar to the Valoy Enlarger with
the exception of the automatic focusing features. The lamp housing,
movable condenser and method of inserting the film in the Focomat
Enlarger is just the same as in the Yaloy Enlarger. The differences
may be mentioned as follows :

146

Enlarging

Fig. 99 Valoy Enlarger,
complete with easel, mag-
nifier, orange filter and
negative masking carrier
plate

Fig. 100 Focoinat Enlarger, complete with
easel and orange filter

1. As shown in the illustration the Focomat Enlarger has two extension
arms which attach the lamp housing to the upright pillar. The upper
arm holds the lamp housing, while the lower arm likewise holds the
lamp housing in a vertical position and at the same time makes the
changes in the focus of the lens.

2. The Focomat Enlarger can be adapted for use with any 50mm Leica
lens.

3. There are three different settings on the focusing ring of this enlarger.
These settings are used with the different film holders, such as, the
regular holder for receiving rolls of Leica film, and also the glass plate
holder which holds the film in a slightly different plane for enlarging.

4. A magnification scale is included.

5. On the upright pillar there are two holes. The upper one is for use
with the enlarger when the paper holding easel is in position. The
lower hole is used for marking the position of the bracket on the lamp
housing when the easel is not to be used.

The Focomat Enlarger is focused with one of the Leica lenses sat the
Leitz Company in New York before delivery. Once this setting has been
made, there is no need for making a change. Any of the 50mm Leica
lenses may be used or the special Varob Enlarging Lens can be used. The

147

Varob lens is really recommended because this lens can be left on the
enlarger continually and it will not be necessary to use the lens from the
Leica Camera.

Fig. 101 Focomat Enlarger which
accommodates all negative sizes up
to 2% x Sy2 inches.

Fig. 102 Vanos Enlarger
for use with all negatives
up to 2% x 3% inches.
Note counterweight for
balancing weight of en-
larger.

Enlarger Accessories

There are various accessories for use with the Valoy and Foco-
mat Enlargers. Masking plates for use with single frame, double frame,
3 x 4cm, and 4 x 4cm negatives may be used in these enlargers. Glass plate
negative holders are also available for enlarging single negatives. The
2% x 3% Focomat and Vanos Enlargers accommodate all film sizes up to
their maximum areas. Orange niters are also of value when making en-
largements or glass lantern slides. A special attachment ring is available
for fitting to the Elmar or Hektor 50mm lenses. This ring permits the
operation of the iris diaphragm by turning a knurled ring with a special
calibrated scale on the side. In this way it is very easy to read the lens
-stops from the side of the ring. As all enlargements should be made with
the lens closed down at least two or three stops, such a ring is recom-
mended. Preliminary focusing is done with the lens wide open.

The Vanos Enlarger

The Vanos Enlarger is designed for enlargement of all sizes of minia-
ture camera negatives. This enlarger will accommodate all films from
the single frame size of 35mm film to 2% x 3% inches. Its optical system
is so arranged that the Leica interchangeable lenses can be used in it. As
standard equipment a 95mm lens is available. The focusing bellows is
adjustable for use with other interchangeable Leica lenses. The Vanos
Enlarger as well as the large size Focomat Enlarger have stationary con-
densers. A special optically flat glass sandwich plate is used for holding
Leica films or cut films up to 2% x 3% inches, otherwise the method of
using the Vanos Enlarger is practically identical with that of the Valoy
or the small Focomat Enlarger.

148

Enlarging

A special Offset Arm is also available for use with the Valoy and
Focomat Bnlargers. This Offset Arm is of special value when making "big
enlargements because the lamp housing is extended an additional 6 inches
away from the upright pillar. As the Offset Arm contains a short rod
itself, it is possible to raise the lamp housing of the enlarger about 18
inches higher than the top of the regular upright bar which comes with the
enlarger. Even when making huge enlargements up to 2 or 3 feet or
greater, this Offset Arm can be used very successfully in the horizontal
position. The arm may be moved vertically or horizontally by loosening
the set screw and turning the attachment in various positions. In the
horizontal position as shown in the illustration, the picture may be pro-
jected upon a wall for making the huge enlargements.

If the Leica lens is used without the Adjustable Diaphragm Ring, the
figures engraved on the lens mount represent the following ratios:

Relative Aperture:
Ratio of Exposure:

1.9 (2.0) 2.5 3.2 (3.5) 4.5 6.3 9 12.5 18
0.36 0.63 1 2 4 8 16 32

Fig. 105 Diaphragm King,
available for Elmar 35mm
and 50mm, and" for Hektor
50mm lenses when these
lenses are used on en-
largers

Fig. 103 Offset arm for
making great enlarge-
ments

Making the Actual Enlargements

Now let's suppose that the Valoy Enlarger has been selected and
we are ready to make our first enlargements. First, check up on the
darkroom equipment and make certain that the following materials
are available:

1. The Valoy Enlarger.

2. Developer, short stop, and hypo solutions as well as trays. The
trays can be selected for the size of enlargements which will be
made. A set of 5 x 7 and 8 x 10 inch trays are always of value.

3. Enlarging paper. (See next chapter on Enlarging Papers).

4. Check up on the proper safe-light and other accessories for the
darkroom use. (See chapter on the Leica Darkroom).

149

Montage by Barbara Morgan Photos by Henry Kloss

All photographs made with Summar 50mm lens, 1/1000 second at f :4.5

Eastman Super-X ftlro Note reversible prints used in design

After all, there is very little equipment required for making
Leica enlargements. You can easily confiscate the kitchen sink and
drain board for this work after the windows have been covered with
a blanket or black cloth. The darkroom chapter will give you more
complete information about becoming a 'bathtub finisher.

Before placing the Leica negative into position in the Valoy En-
larger, make certain that there are no dust particles clinging to the
film. If there are, remove them with a soft brush or with a clean
lintless linen cloth. The movable condenser should always be in-
spected for dust or dirt particles. These points are very essential
because small dust particles may spoil an otherwise perfect enlarge-
ment if they are not removed beforehand. The Negative Viewer and
Marker can be used very successfully for picking out the best nega-
tives for enlarging. "With this attachment, it is possible to make a
small nick in the edge of the film. Then, while working in the dark-
room, the negatives can be picked out very quickly by running a
thumb along the edge of the film.

When the correct negative has been selected, insert the film into
the negative carrier of -the enlarger with the emulsion side down.
Snap on the light and move the film so that it appears in the frame
which is projected down onto the paper holder. This can be done
while the condenser is in the raised position. Next, move the clamp-
ing lever forward in order to release the condenser and thus clamp
the film into a plane position. Now, raise or lower the lamp housing and
turn the focusing mount, into which the Leica lens has been screwed,
until sharp focus has been secured over the entire picture area.

Some Leica workers secure' critical focusing by placing special
negatives with sharp line drawings in the enlarger before the regular
negative to be enlarged is inserted. Then, when perfect focus is se-
cured by projecting the lined negative onto the enlarger easel, the
focusing negative is removed and replaced by the regular film strip.
A black over-exposed frame can also be used for this purpose provid-
ing a few fine scratches are made on the emulsion side of the film.

A hand magnifier or reading glass can also be used for viewing
the projected image on the enlarging easel. Sometimes this latter
method is very convenient for securing critical focus.

The enlarging easel should be set for the proper size of the enlarg-
iftg Paper- The two adjustable masking bands can be moved for
making the proper adjustments. It is best to have a small white
margin around the finished enlargement. This white margin can be
varied according to requirements.

152

Enlarging

After the projected negative is properly focused and centered
on the enlarging easel, you are now ready to make an exposure test.
Select a small strip of enlarging paper and place it on the easel with
the emulsion side up. Stop the lens down to one or two diaphragm
stops. A small pencil flash light may be used to make the adjustment
of the lens diaphragm. This flash light can be covered with a piece of
red paper. With the proper lens stop set you are now ready to snap
on the switch and expose the test strip. Two or three different ex-
posure times should he made on this test. A small card can be moved
across the test strip at one or two second intervals, depending upon
the speed of the paper and also the density of the negative. With a
little practise it is very easy to count seconds without watching a
clock. There are various methods used for counting. For example,
seconds can be counted in this way: Thousand 1 — Thousand 2 —
Thousand 3 — . Or, if this may be too monotonous, try the following :
1 chimpanzee, 2 chimpanzee, 3 chimpanzee, etc. There are excellent
darkroom clocks with second hand dials for use in timing negatives on
enlarging papers.

The diaphragm stops on the enlarging lens can be more easily
seen if a small white card is placed just below the lens in order to
throw the reflection of the light back onto the lens. The card can be
bent in such a way that the light will even be thrown around to one
side of the special attachment ring in case it is used for adjusting the
diaphragm stops.

After the test strip has been exposed, place it in a developer and
develop for a full time of iy2 t° 2 minutes in case of bromide papers.
If the slow chloride contact paper is used, the developing time will
probably be about one-half the time required for bromide paper.
After the test strip has been fully developed, rinse it in the fixing
bath for a few seconds and then turn on the white light and examine
the exposures. The correct exposure can usually be determined very
quickly. Now place a full size sheet of enlarging paper in the en-
larging easel and snap on the light for the required length of time.
Remove the paper and place it in the developing tray. After proper
development, rinse the picture in the acetic acid short stop which is
made up as follows :

Acetic Acid (28%) 1l/z oz. 48 cc

Water 32 oz. 1000 cc

From the short stop the print is placed in the acid fixing solution for
about 15 minutes. See the next chapter on Printing Papers for in-
formation about the acid fixing solution.

153

After the picture has been thoroughly fixed, it should be washed
in a tray in running water for at least one hour before placing out to
dry on blotters or in the special blotter roll which is now available.

Estimating Print Density

Some people have a very easy time turning out excellent prints which
embody everything- that is known as quality. Others have a hard time
making good prints. It is true that some people have a gift for such
work, having the ability to put quality into their prints by instinct or intui-
tion, but even the average person who lacks that spark should be able to
turn out most satisfactory prints after once getting the feel of making
them.

Let's see what is involved in the process of producing a latent image
upon a sensitized paper and subsequently converting that latent image
into a real image in terms of black and white and the intermediate tones
of these two colors.

The emulsion of the paper coats the surface very similarly to that of
a coat of paint* Paint consists of a vehicle, which is usually linseed oil
or other more or less volatile substance, and tiny particles of pigments
suspended in the vehicle. The emulsion of the sensitized paper consists
of gelatine, the vehicle in which particles or grains of light-sensitive sil-
ver bromide, chloride or a mixture of both are suspended. The emulsion
has a thickness. This thickness may vary with the different types of
papers. There are particles of sensitive silver salts that are near the
upper surface of the emulsion and some that are joined to the surface
of the paper. And there are particles of these salts scattered in between.
When light strikes the surface of the paper, after passing through the
negative, it strikes the sensitive silver salt grains. If little light reached
the surface of the emulsion, only those silver grains become affected by it
that are nearest the surface. The more light that reaches a certain point
of the paper, the deeper it penetrates into the emulsion and the more par-
ticles of silver salts are affected by it. Obviously a certain na|xamum
amount of light must be admitted to the surface of the paper tC affect
the lower layers of silver salts imbedded in the emulsion.

After exposure, the latent image produced upon the emulsion of the
paper must be developed through conversion of the silver salts into
metallic silver grains. When the print is immersed in the developer its
chemicals begin to react with the silver salts in the emulsion after the
water of the developer softens the dry gelatine. The particles of developer
gradually penetrate into the thickness of the emulsion until they reach
all the way through it to the paper proper. Obviously a certain minimum
of time must elapse between the time when the uppermost grains of silver
are developed and the time when the lowermost grains are converted
into silver.

This is the reason for the requirement of paper to be developed for
a minimum time before withdrawing it from the developing solution. In
most instances that minimum time for bromide and chlorobromide is set
at one and one-half minutes. That is the minimum time of development.
If after the printing has been developed for one and a half minutes, and
not less, it appears weak and flat, it apparently has been underexposed and
more exposure should be given. If it appears to' be too dense it has been
apparently overexposed and the subsequent exposure should be shortened.

154

Enlarging

Longer development than the minimum of one and a half minutes is
frequently indicated. Some prints acquire a certain tone quality through
longer development. Thus it can be said that with certain developers
for instance after a minute and a half development almost all details
of the picture are available and the development is continued for another
half minute with very little apparent change taking place in the print.
But when finished and dry such print will have that quality and richness
which we always look for.

An excellent and frequently overlooked method of learning how to
make good prints consists of making some prints on lantern slides or on
positive cut film. The emulsion of lantern slides and positive cut film is
similar to that of bromide papers. Lantern slides and transparencies made
on positive cut film have a greater brilliance and greater latitude than
bromide papers. This is only measurably true. Their emulsions being
almost the same, the difference of quality results from the viewing method
employed, slides being viewed by transmitted light while bromide prints
are viewed by reflected light. This difference will become quite apparent
when^one will visualize a cross-section of an emulsion similarly exposed.
Bromide paper emulsion and lantern slide or transparency emulsions of a
similar negative would show under great magnification that the densities

Fig. 107 Reflections

of the deposit of black silver grains are almost identical and they form
terrace-like recesses or slopes ranging from blackness merely at the sur-
face of the emulsion to total blackness of the entire thickness of the
emulsion. It is easy to see that transmitted light penetrates through these
layers of different degrees of blackness with a different intensity, thus
forming degrees of intensity that can be likened to shades of gray. Light,
however, that is reflected from a black surface backed with white paper
can produce only a very limited range of tones of gray which would de-
pend on the thickness of the black.

Thus if one would use positive cut film or lantern slide stock instead
of bromide or chlorobromide papers for enlargements or portions of en-
largements one will begin to evaluate these differences of the thickness
of silver deposits. Lantern slides or transparencies must be viewed by
transmitted light. Viewing them in a developing tray will produce un-
favorable, erroneous results. A transparency that may look fully devel-
oped in the tray will look flat when viewed against a light box. And one
that looks totally black in a developing tray will show excellent brilliance
and contrast when viewed against an adequate light source. A dozen
lantern slides or pieces of positive cut film would be an excellent invest-
ment and one will get more information from such experiments than from
a whole volume written on the subject. That is the only way to get the
feel of the matter and it cannot be recommended strongly enough. Later
on, after having made a number of prints in the form of transparencies
one may adopt the same method for judging prints: when they are devel-
oped according to a standardized method and fixed, view them against some
strong source of white light, while wet, and if your print looks good that
way, it certainly will be good when dry and finished.

Prints should be wet when viewed through transmitted light, particu-
larly those made on double-weight paper which may require a stronger
source of light than those made on single-weight paper.

Incidentally it should be remembered that lantern slides and cut film
transparencies can be developed in the same developers which are used for
developing of bromide or chlorobromide papers.

Printing Control During Enlarging

The enlarging of a negative permits much greater latitude in
the actual printing control as compared to contact printing. During
enlargement, it is possible to introduce soft focus lenses, special dif-
fusion screens, and also use special paper masks or other means of
dodging the picture during exposure. While contact printing permits
very little variation in the finished print, a little shading is about all
that can be done above the negative during exposure.

Dodging may be necessary when printing a negative in which the
sky is considerably overexposed while the foreground may be normal
or even underexposed. The correct exposure is made for the fore-
ground and then a cardboard is used to mask out the foreground while
the sky is given a few additional seconds in order to bring out the
clouds or to keep the sky from printing white. With a little practice

156

Enlarging

Fig. 108 Tea Time

Morgan Heiskell

and ingenuity the operator can devise various methods of dodging or
shading. For example, a large cardboard can be cut with a round
hole through which the picture may be projected as required for
bringing out certain effects in the print. Also, small cardboard
discs can be attached to a thin wire when it is necessary to hold back
certain portions of the picture during exposure. In case there is con-
siderable dodging to be done on a print, the diaphragm on the enlarg-
ing lens can be stopped down several stops more in order to give a
longer working time. During the shading process, it is quite essential
to keep the cardboard moving in order to prevent a sharp line from .
appearing where different exposures are made. A little practise will
eliminate this trouble. Many enlargements can be shaded simply by
moving the hand below the enlarging lens and thus blocking out any
part of the picture which may be necessary.

Still other methods of control are possible by using a supple-
mentary soft focus lens in front of the enlarging lens or a thin piece
of tulle may be mounted in a holder and moved around just under the
lens during the exposure. Also, special effects may be secured by
placing screens directly over the enlarging paper. Sometimes these

157

screens are printed on glass plates in order to give a small space be-
tween the screen and the paper and thus permit a slightly softer
result. Still another method of obtaining special effects on the en-
largement is by using a clear glass plate with fine sand sprinkled
around the plate where the background of the picture is to be held
back or diffused. For example, the backgrounds of portraits may be
printed by this method.

Although many people like to use these special methods of secur-
ing certain results, the ideal way is to make the enlargement naturally
without diffusion or the use of special screens which only give a false
effect in an attempt to imitate etchings and lithographs. It is not
necessary to make the original Leica negative through a diffusion lens.
Once a sharp negative is available, it can be used for any purpose
thereafter.

Some enlargements may be greatly improved by skilfully using an
ordinary flash light for overexposing certain areas, while the rest of the
paper is covered. In doing this, the orange filter is moved over the lens
of the enlarger in order to prevent exposure on the paper. However, the
projected red image will guide you in flashing the light over the areas
which are to be darkened. Thus a sky may be made almost black for spe-
cial effects, or, the background of a portrait may be darkened or graded
off. Still another method of using a flash light is for making a small
narrow black margin around the printed picture while it is still in posi-
tion in the enlarging easel. To do this, cut a sheet of cardboard slightly
smaller than the final picture will be. This cardboard is placed over
the sensitized paper in the enlarging easel. By moving the card into one
corner there will be two sides left with a margin of possibly % or %
of an inch. Slowly pass the flash light along this exposed margin. Then,
push the card into the opposite corner and continue around the other two
sides. When the paper is developed, the image as well as the black
margin will appear on this same print.

The Use of Photoflood Bulbs in the Enlarger

With the introduction of the photoflood bulbs, it is now possible to use
greater illumination in the Leica enlargers. With a photoflood bulb, the
slow chloride contact papers can be used very successfully. As these
papers require considerably longer exposure as compared to bromide papers,
the photoflood illumination is perfect for making the exposures. Very
dense negatives can likewise be used with the higher illumination available
from photoflood bulbs.

A rheostat or illumination control is recommended for use with the
photoflood bulbs. Such controls are available at your photographic dealer.
The Leitz Illumination Control is made for one photoflood bulb and contains
-seven different stops for varying the intensity of the illumination. Also,
there is another illumination control known as the Variac manufactured by
the General Radio Company in Cambridge, Mass. The Variac Transformer
can be used for delivering voltages between zero and 130 volts from the
115 volt circuit. The Variac does not overheat if operated continuously

158

and this transformer will control any number of photoflood lamps tip to
four. Such a method of controlling the photoflood bulb in the enlarger is
ideal because it is not always necessary to have the bulb burning: at its
brightest intensity for making- enlargements. By turning down the volt-
age and using the bulb at less illumination, it is very easy to do all the
focusing of the negative and thus prolong the life of the photoflood bulb as
well. The Variac Transformer is designed for use on alternating current
lines only.

It should be noted that only photoflood bulbs especially designed for
enlarging purposes should be used. Ordinary photofloods have the manu-
facturer's emblem at the tip of the bulb which will cast an objectionable
shadow upon the image. This emblem cannot be removed by ordinary
methods. Special enlarger photofloods are made with the manufacturer's
emMem placed along the bulb's neck. Subsequently a photo enlarger bulb
made by the General Electric Co. frosted inside and out for better diffusion
is known as the 200 watt, 105 to 120 volt photo enlarger bulb.

Occasionally a photoflood bulb may break or crack in the enlarger.
Therefore, it is a good plan to place a small square of clear glass over the
movable condenser in order to prevent it from being scratched by a bulb
which may possibly break. Also, a special ventilating ring is available for
placing below the upper half of the lamp housing. This ventilating ring will
keep the enlarger from overheating when the photoflood bulb is burned for
any length of time for making the longer exposures.

Frequently it is possible to make a number of interesting" pictures
from one negative. In other words, a negative may contain two or three
different compositions of special interest. Individual portraits can be
selected from a group picture by greater enlargement of the negative.
Naturally when negatives are to be enlarged to any considerable size,
it is quite essential that they have fine grain development in their original
processing.

Reduction of Leica Negatives by Projection

In the chapter on Making Leica Film and Glass Positives, there
is special information about reducing Leica negatives, or, printing
Leica negatives in natural size. Considerable interest may be created
by preparing a series of Leica enlargements as well as a number of
Leica reductions from the normal size of Leica negative. "When making
the small prints, a 3, 6 or even 9cm Extension Tube may be placed be-
tween the enlarger and the enlarging lens. In this way it is even pos-
sible to reduce a Leica picture to 1/4 of an inch in diameter if neces-
sary. Such small miniature pictures may be used for ring or locket
settings as a novelty.

Micro slides can be successfully enlarged by direct projection in
one of the Leica Bnlargers. Many medical and professional workers
will find this method of enlarging micro sections of special value for
study and filing purposes.

159

Pig. 110 Gear Cutting

Suminar 50mm lens, 5 seconds at f:12.5
Perutz Persenso film

I. Luckman

Contact Printing

It is also possible to make your "contact" prints by projection.
Once the correct setting has been determined, the entire strip of film
can easily be printed within a. few minutes after a few test strips have
been made. With a little skill it is also possible to print all these
test strips onto one large sheet of paper and then the entire sheet
placed in the developer. This method is recommended for filing pur-
poses especially. The individual prints can be numbered and the
number of the roll as well as any other data may be placed at the top
of the sheet of paper. If desired, a master negative 8^5 x 11 inches
in size could be made for printing the numbers as well as the outlines
of the picture spaces before the contact prints are made on the sensi-
tized paper. For this purpose, a special enlarging easel can be con-
structed with notches or guide lines and, the easel is thus moved
from frame to frame as the prints are made.

Actual contact printing is done by placing the Leica negative in direct
contact with the sensitized photographic paper. The emulsion, or dull side
of the negative, must face the emulsion side of the paper. In other words,
contact printing is really natural size printing where the printed picture is

160

exactly the same size as the original negative. While working in the dark-
room one may be doubtful about the emulsion side of the paper. A quick
test can be made by touching the tongue at one corner of the paper. The
side which feels slightly sticky is the emulsion side which is also slightly
shiny.

The most elementary way to make a contact print is to place a strip
of photographic paper, emulsion side up, on a smooth surface. Then, place
the negative face down on the paper and force complete contact by pressing
a glass over both. This setting is naturally done under the usual darkroom
safelight for paper. The white light is turned on for making the exposure
on the contact print. The enlarger can also be used as a light source for
this purpose very readily. In case the enlarger light is too strong, one or
two sheets of tissue paper placed in the film plane of the enlarger may be
used to soften the illumination. After exposure the paper is developed.

However, most workers prefer a neat printer for making their contact
prints. Such a printer can either be made or purchased. The Eldia, Eldur,
and Laver Printers supplied by the Leitz Company can all be used for
making paper contact prints as well as for contact printing on film or glass
slides. The Willo strip printing frame made by Willoughby's or the Agfa
printer can also be used for printing single frame and double frame
negatives.

The chapter on Printing Leica Positives gives detailed information
about using the Eldia, Eldur and Laver Printers. These printers are also
illustrated in that chapter. In the Eldia Printer, the paper can be wound
around the spool with the negative. Then, the empty spool on the opposite
side of the printer is turned so that the paper and film both advance at
the same time. The exposures are made by turning on the enlarger light
or any other strong source of illumination may be used. This same method
of printing can likewise be used in the Laver Printer. The Eldur Printer
and also the Glass Slide Printing Attachment for the Laver Printer can be
fitted with a small metal pressure plate for use when making individual
contact prints on 2 x 2 inch paper which has been previously cut for the
purpose.

A number of Leica users have even made a contact printer by taking
two pieces of plate glass cut 5 foot strips and 35mm in width, or the exact
size of the film. One side is hinged with tape. With this printer it is very
easy to place a negative film in position and a strip of unexposed contact
paper over the film. The two glass plates hold both in perfect contact
during the exposure when the white light is turned on. Such a method
is very rapid although it is necessary to make a normal estimate of the
exposure for the entire strip or film.

Single contact prints or paper strips containing 4 or 5 exposures can
easily be developed in trays. However, when longer strips of 3 or 5 feet
are to be developed, it is necessary to use a special developing tray with a
roller weight at the bottom under which the paper strip is passed. During
development, the paper strip is quickly passed back and forth through the
developer in the tray. Such developing trays may be secured from your
photographic dealer. These trays can also be used for developing film
strips if special care is taken. WJien using the Azo 35mm perforated or
unperforated paper which may be secured in 200 foot rolls, the developing
time will be approximately 45 seconds, when using the D-72 Eastman
Formula at a dilution of one part of developer to two parts of water. A
different developer and time must naturally be given when developing nega-
tive or positive films in this type of tray.

Still another method of developing strip paper is by using the Correx

161

or Reelo Developing- Tanks. The paper is wound into the reels similar to
the method used for inserting and developing film negative strips. When
development is complete, the reel can be quickly immersed in a short stop
solution for a few seconds and then placed in the fixing bath. If additional
paper strips are to be made, the paper must be unwound from the reel, the
reel and apron are then thoroughly washed in running water before using
again for development. The exposed strip of paper should be left in the
fixing solution for at least 10 minutes.

The Agfa Ansco Company supplies the fast Brovira paper in perforated
35mm width for contact printing. The Azo paper supplied by the Eastman
Kodak Company as well as the Brovira paper may be secured in the
various degrees of contrast.

After the contact print has been made, the single prints can be
mounted for quick reference for indexing purposes on individual
cards or in a special photo album. Special mounting masks are avail-
able for preparing the individual contact prints for filing. There is
also the "Willoscope available for viewing single contact prints. This
little device has a magnifier and also a place to hold the single contact
print for viewing. This viewer also contains a space for the contact
prints and at the same time it can be folded in a very small space and
carried in the pocket. The method of printing or mounting the indivi-
dual pictures on a sheet 8% x 11 inches in size may be of great value
for filing purposes. In fact, contact prints could be used more gen-
erally than they are, not only for filing purposes and keeping track of
negatives, but also for making attractive contact print albums. Con-
tact prints assembled according to subjects and special layouts with a
few captions would certainly make an attractive album. It is sur-
prising how much may be seen even in a small contact print.

Mountain Scene

Elmar 35mm I/SO f :5 Agfa Superpan, medium yellow filter.

Ernst Schwarz

162

JERT M. LUDLAM CHAPTER 8

The average user of a miniature camera is having relatively little
culty in turning out negatives of reasonable quality. Exposure
ers representing but a fraction of the first cost of the camera have
linated the guess-work in negative making, particularly since
iature negatives are developed uniformly for a given time at a
d temperature. Nevertheless, the prints of most workers do not
n. to satisfy them, and one is continually asked, "Why don't my
its have lifer9

The answer is fundamental to miniature photography. In order
>btain a minimum grain size, we are using developers of very low
rer and are developing only to some point of compromise between
mal contrast and the smallest grain. Photographers using larger
atives develop in solutions of considerable power and carry de-
>pment much further. Consequently, the contrast of their nega-
s is considerably greater than that of ours. Years before the
ent of miniature photography paper manufacturers recognized

need for papers whose inherent contrast corrected for mistakes
levelopment and began producing papers in several degrees of
trast (soft, medium, hard, etc.). It was found that a negative
a certain contrast had become the accepted standard and the
mfacturers designated as normal, or medium, that paper which
duced the most pleasing print from a negative of this quality.
3e the formulas recommended by manufacturers in every paek-

of paper are based on this average negative, we must consider
negatives in the class which manufacturers call weak or flat nega-
is and accordingly must use the contrasty formulas or papers
)mmended for such negatives.

Because of the misleading nature of the term normal or medium
ipplied to papers, most workers in miniature photography believe
b they should not have to use any other paper if their negatives
e been correctly exposed and developed. Kather should the be-
ner, if he must follow a hard and fast rule, consider the use of

163

papers of greater than normal contrast as being the standard with,
miniature negatives. In those cases where the paper is furnished in
only one grade the contrast formula recommended by the manufac-
turer should be used. If this rule is followed, nine out of every
ten negatives which at present are unsatisfactory will become valu-
able additions to the tyro's file.

«*

Choice of Paper Stocks and Surfaces

Printing papers today are produced in so many surfaces that it
would be impossible to give any comprehensive list. Different manu-
facturers use widely differing designations for papers of very similar
surfaces, so that the only satisfactory way of choosing some special
surface is through an inspection of samples. If the prints are to be
reproduced they should be made on glossy paper and ferrotyped
unless the reproduction is to be considerably smaller than the original,
in which case semi-matt papers are quite suitable. One of the most
beautiful surfaces is obtained by using a matt or rough matt paper
and waxing the finished print with a waxing solution obtainable in
any photo supply house.

The paper stocks most commonly used are white, cream and buff;
the most common weights being the single weight, generally used for
contact work, and the double weight or light card, usually associated
with enlargements. Prints which are not to be mounted in albums
or on regular mounts are much more satisfactory on double weight
stock, while prints for mounting, particularly in albums, are best
made on single weight stock. No hard and fast rule, however, can
be attempted. "With, regard to the color of the stock itself, it should
be remembered that black and white prints are not satisfactory on
buff tinted mounts, nor are buff tinted stocks satisfactory on gray
mounts; white, however, is satisfactory with almost any stock.

Tone Gradation

It is impossible to reproduce on paper every gradation of gray
available in the negative. This holds true of contact printing as well
as enlarging. Sensitized paper has a much shorter scale than nega-
tive material. The reason for this is the fact that a picture is seen
on paper by reflected light while a negative is examined by trans-
mitted light. The white of the paper will not reflect more than 50
per cent of the light falling on it while the blackest part of the print
will still reflect at least 2 per cent of the light leaving a difference in
tone of perhaps 25 to 1 as compared with 60 to 1 in the negative, since
the densest part of a negative may only transmit one-sixtieth of

164

first learn to make excellent pictures with the fundamental process
of photography.

Generally the tone gradation scale is shortest in fast projection
papers and is longest in slow papers. It is claimed that the longest
scale range can be obtained in contact or so-called chloride papers.
Contact papers are available in as many as six grades of contrast
while projection papers only in two or three. Thus the choice of a
proper degree of contrast in contact paper will enable one to obtain
sometimes a better print on contact paper than on projection paper,
provided a suitably strong light is available. Although I have my-
self recommended the use of contrast grades of paper at the begin-
ning of this chapter and again here, it must be remembered that this
is only for beginners. Normal and soft grades of paper produce
beautiful middle tones even in the contrast developers recommended
by the makers. Contrast, hard, vigorous papers etc. have not as
yet been perfected to the point where they can produce the full
tone scale of a medium grade paper. The more advanced worker
has found other means of building up the contrast, either in develop-
ment of the negative or in later steps such as the enlarged negative
processes. However the beginner will get very acceptable prints by
following the simple process of using the contrast grades of paper or
the contrast developers.

Fast Projection Papers

Fast projection papers are commonly known as bromide papers because
silver bromide is the sensitive agent in their emulsions, in fact, the emulsion
is very similar to that of slower plates and films. Most of these papers are
made in several degrees of contrast as well as a variety of surfaces and
stocks as mentioned above. Some idea of the papers commonly used, which
fall in this class, can be obtained from the following list :

Brovira produced by the Agf a~Ansco Company
Velour Black Defender Company

PMC Bromide Eastman Kodak Company

Novabrom Gevaert Company

Press Bromide Haloid Company

Ilford Bromide Ilford Ltd.

Wellington Bromide

Wellington & Ward Ltd.

Slow Projection Papers

Slow projection papers are known as chloro-bromide papers because
their emulsions are made up of both chloride and bromide of silver. Be-
cause of the presence of silver bromide these papers are considerably faster
than ordinary contact papers whose emulsion is made up entirely of silver
chloride; they are therefore suitable for enlarging, the exposure in gen-
eral being approximately four times that necessary for a regular bromide
paper. The long range of tones which can be obtained with, these papers is
making them very popular for portrait and pictorial work as is also their

166

Enlarging Papers

moderate speed which makes them available both for direct enlargements
and for contact prints from paper negatives. The papers most commonly
used, which fall in this class, are as follows :

produced by the Agfa-Ansco Company

" " " Dassonville Company

" " " Defender Company

" " " Eastman Kodak Company

tt cc tc <t it ((

" " " Gevaert Company

" " Haloid Company

" " Ilford Ltd.

« « Wellington & Ward Ltd.

Indiatone

Charcoal Black

Veltura

Illustrators' Special

Vitava

Gevalux

Projecto

Clorona

Mezzotint

Contact Papers

Contact papers are often called chloride papers because they depend
for their sensitivity on chloride of silver alone. Being very slow they were
seldom used for enlargements until the development of the photo-flood lamp
and its use in miniature enlargers. Proper selection of the contrast of the
paper will reward the user with very pleasing results. There are so many
contact papers available on the market today that any attempt to list them
would be wholly inadequate. However, contact papers manufactured by the
firms making the projection papers listed above are as follows:

Convira

Apex

Azo & Velox

Novagas

Industro & Nomis

SCP

produced by the Agfa-Ansco Company
" " " Defender Company
" " " Eastman Kodak Company
" " " Gevaert Company
" " Haloid Company
" " Wellington & Ward Ltd.

Wickie and Suzanne

Siaxnmar 50mm, f:6.3 Peromnia Film.

Ed. Schaefer

Development

The following tables give the formulas recommended by the
paper manufacturers for their papers most commonly used in en-
larging. The formulas have been grouped in three classes, soft,
medium and hard, but it should be remembered, however, that the
hard formulas are the ones which should be used with papers pro-
duced in only one degree of contrast as their natural contrast falls
in the class of medium papers.

SOFT PAPER DEVELOPERS

Metol 80

Sod. Sulphite 438

Hydroquinone 24

Sod. Carbonate 328

Pot. Bromide 15

Water to make

NvBr
Grains Grams

5.7
31.0

1.7
23.0

1.1

GVA
Grains Grams

29
350

280

Avd. — 32 Ounces

2.1
25.0

3.0
20.0

1.0

D64
Grains Grams

26
185

145
19

1.8
13.0

2.0
10.0

1.4 lH-

Metric— 1000 cc

Artura
Grains Grams

164

20.5
64

1.6
12.0

1.5
4.5
0.8

Novabrom really suggest using any mixture between their softest
and hardest formulas to obtain the particular contrast required.

NyBrMed
Grains Gram
48 3.4
356
40
328

25.0
2.9

23.0
1.1

MEDIUM PAPER DEVELOPERS

D7S Artura D52 Haloid V.B.

Grains- Grams Grains Grams Grains Grams Grains Grams Grains Grams Grains Gram!

Metol

0.6.
9.3
2.5

14.0
0.4

13 1.0
193 14.0
32 2.3
365 27.0
4 0.3
Avd.— 32 Ounces

178
41
136
6

0.9
13.0
2.9
10.0
0.4

11 0.8
164 12.0
45 3.2
109 7.7
11 0.8
Metric— 1000

12
176
48
176
6
cc

0.9
12.5
3.4
12.5
0.4

16
164
48
273
16

1.1
12.0
3.4
19.0
1.1

Sod. Sulphite
"Hydroquinone . . .
Sod. Carbonate..
Pot. Bromide
Water to make

, 131
. 35
, 197
, 6

Soft

Agfa

Grains Grams

Med.

Agfa

Grains Grams

NvBr
Grains Grams

Metol

Sod. Sulphite ..
Hx^lroquinone . .
Sod. Carbonate
Pot. Bromide .
Water to make

219

278
5

1.0
16.0

3.6
20.0

0,4

D64
Grains Grains

17
274

55
383
6

Avd. — 32 Ounces

1.2
19.0

3.9
27.0

0.4

16
274

56
328

1.1
19.0

4.0
23.0

1.1

13
185

66
145

Metric — 1000 cc

1.0

13.0

4.7

10.0

1.4

Wei.
Grains Grams

16
560

560

l.l
40.0

3.4

40.0

0.4

VIGOROUS PAPER DEVELOPERS

GVA

Grains Grams
Metol .................. 21 1.5

Sod. Sulphite .... ...... 350 25.0

Hydroquinone ......... 80 5.7

Sod. Carbonate ........ 525 37.0

Pot. Bromide .......... 15 1.1

DsV

Grains Grams

24 1.7

328 23.0

83 5.9

219 15.0

31 2.2

D64
Grains Grams

.
Avd.— 32 Ounces

Dn*

Grains Grams

13 1.0 14 1.0

277 20.0 1094 80.0

117 8.3 130 9.3

217 15.0 360 25.0

25 1.8 70 5.0

Metric — 1000 cc

Water to make

*D11 is for positive film and is shown to indicate the high sulphite content required for fih
processing as compared to paper. , *wuw«su lor nil

NvBr-~Novabrom. GVA-Gevalux. V.B.-Velour Black. DsV.—Dassonville.

Several two-solution developers could be recommended for use
with papers produced in only one degree of contrast. The purpose
of separating the developer into two stock solutions is to permit the
contrast of the developer to be altered by altering the proportion of
the two stock solutions. It will be noticed in the previous tables that
Eastman's D64 formula approximates the average in each contrast
group.

168

Enlarging Papers

To those workers who may object to a formula requiring two or
three stock solutions, a universal developer formula is offered with
the full confidence that it will prove invaluable as an all-round
developer for everything except negative films. This formula is
comparatively simple to prepare, keeps almost indefinitely, produces
beautiful tones on almost any kind of paper, can be used successfully
not only for contact papers and projection papers but also for lantern
slides, positive films, transparencies, etc. This formula approximates
Eastman's D52, which our table indicates as of medium contrast.

Universal Developer

Water (at 125° F)

Metol

Sod. Sulphite (dry)

Hydroquinone

* Sod. Carbonate (dry)
Pot. Bromide

Methyl Alcohol (wood alcohol)
Cold Water to make

* If Monohydrated Sod.
Carbonate is used

16 ounces
75 grains

2l/2 ounces
300 grains

Zl/z ounces
75 grains

4% ounces
32 ounces

500 cc

5 grams
75 grams
20 grams
105 grams
5 grams
150 cc
1 liter

4 oz., 10 grains 120 grams

Dissolve above chemicals in the order given. It will be found that the
Hydroquinone and Carbonate will not dissolve completely until after the
wood alcohol is added. It will be found helpful to mix the alcohol with an
equal amount of cold water before adding- it to the solution. Add alcohol and
water mixture slowly while stirring. The solution will gradually clear.
Filter it into an amber glass bottle. It is ready to use as soon as cool.

This developer works best at approximately 70° F. It should be diluted
as follows:

Stock Solution Water

For Bromide papers, lantern slides, positive film,

transparencies 1 part 6 parts

For Chloro Bromide papers (slow projection) 1 part 4, 5 or 6 parts

For Contact papers . 1 part 3 parts

Many photographers like the rich blacks obtainable with an amidol
formula such as the following:

Amidol Developer

Water
Sulphite
Amidol
Pot. Br.

32 oz.
328 grains
10-30 grains
50 grains

1 liter
23.4 grams
3.6 grams
0.7 to 2.1 grams

The chief difficulty with amidol is the staining of fingers and the necessity
•of preparing fresh developer each time it is used. The developer rapidly
oxidizes with use, becoming discolored and unserviceable within an hour or
so. The addition of 50 grains (3.5 grams) of Pot. Meta-bisulphite to the
Sulphite solution when mixing the developer will considerably lengthen its

169

useful life, particularly if the sulphite and meta-bisulphite are boiled to-
gether for several minutes. In using this developer, papers manufactured
in several different contrasts must be used, inasmuch as little change can be
effected by altering the developer.

The staining of the fingers will not occur if the precaution of rinsing
the fingers every time they have been in solution is observed. This should be
done in all developing to avoid carrying back into the developer the oxidized
solution left on the fingers.

Altering Developers

The amount of bromide given in the stock solutions is the mini-
mum amount required to keep the highlights clear; it may be in-
creased from this point, increasing the warmth of tone, up to the
degree of warmth manifested in an olive brown tone. The maximum
is about 40 to 50 grams per 32 ounces of ready to use developer.

Aside from modifying the bromide content of developers, varia-
tions can be obtained by adjusting the proportion of metol, hydro-
quinone and carbonate in any MQ developer. For instance, to gain
additional contrast, the Hydroquinone, Potassium Bromide and Car-
bonate can be increased in equal proportion. The increase in bro-
mide is necessary to prevent too vigorous action and will not appre-
ciably alter the color of the print, the additional carbonate offsetting
this tendency as well as increasing the developing action. For softer
results the metol can be increased considerably if the hydroquinone
is decreased proportionately and, if extreme softness is required, the
carbonate can also be decreased. Decreasing the carbonate slows up
development and gives olive tones, whereas increasing the carbonate
increases the speed of development and gives very black tones.

So much for developers. Each package of paper and every maga-
zine offers some variation of the foregoing with sufficient instructions
to cover their preparation and use. Because of the complex nature
of the developing process and the uncertainty of results, if different
developers are used, it is advisable for the beginner to definitely
choose one formula and stick to it until he has learned to produce
consistently satisfactory results with it, making only such modifica-
tions as seem necessary to obtain greater or less contrast or colder
or warmer tones.

Exposure

This brings us to the most difficult problem of all, determining
the correct exposure for the print.

It should be borne in mind that the final print density is the
result of both exposure and development, thus if a- test were made
and the test strip developed for say two minutes, the subsequently
correctly exposed print should also be developed for two minutes.

170

Enlarging Papers

However, having determined the exposure by these means, it is
still necessary to make one or more tests before the final exposure will
be decided upon. Most of us in making test prints attempt to conserve
our paper by using a small strip, and find it extremely difficult to
decide from an inspection of the strip whether or not the exposure
really was correct. It has been my experience that if the test in-
cludes the whole picture it could be extremely small (same size as
the negative) and still a very good estimate of the necessary varia-
tion from the exposure given could be made; far better than from a
test strip the same size or larger comprising but a small portion of
an 8 x 10 enlargement.

Therefore, I prefer to make my test prints 2x3 inches in size
using the entire negative. Prom this slight enlargement (2x) a
quite critical examination can be made in bright light after the
print has fixed for a minute or two. Not only can the correct ex-
posure be determined but the picture itself can be studied. By cut-
ting an 8x10 sheet into four -strips each two inches wide a total of
twelve 2x3 test prints can be made with very little waste of paper.

All tests for an evening 7s work are made at one time and a
record of the correct exposures kept. Sufficient fresh developer must
be used so that it will not deteriorate appreciably. The correct
exposure for the final print is then determined by multiplying the
correct exposure for the test print by the necessary factor to com-
pensate for the increased enlargement, as given in the table below :

Exposure Factors at Various Magnifications

Size of Enlarged MULTIPLYING FACTOR

Image of Full Negative

if original test print was:

(Neg. 1x1% in.)

1x1% in.

2x3 in.

#JL£% in.

1x1% inches

2x3

3x4%

4x6

5x7%

6x9

7x10%

8x12

9x13%

10x15

11x16%

12x18 *

13x19%

14x21

15x22%

171

Another table which proved very helpful is that of squares of
certain basic stop values:

f: Values: 1.9 2*2 3.2 3.5 4.5 5.6 6.3 8 9 12.5 18 25

f : Values

Squared: 3.6 4.8 10.2 12.2 20.3 31.4 39.7 64 81 156 324 625

RATIO OF EXPOSURE: FIRST STOP USED TO PROPOSED STOP.

First Stop

Used— f

Proposed Stop — f:

1.9

2.2

3.2

3.5

4.5

5.6

6.3

12.5

18 25

1.9

90 170

3.5

1/3

1/2

30 50

6.3

1/10

1/4

1/2

3/4

8 16

12.5

1/40

1/30

1/15

1/10

1/8

1/5

1/4

1/2

2 4

1/100

1/70

1/30

1/15

1/10

1/8

1/5

1/4

1/2

1 2

1/200

1/100

1/60

1/50

1/30

1/20

1/15

1/10

1/8

1/4

1/2 1

A few examples I believe will suffice to show the use of these
tables.

First, supposing we have made a test print using the full nega-
tive enlarging it to 3x4% inches. The correct exposure was 10
seconds at f :6.3. Our final enlargement is to be 11x14 losing only
a small portion of the negative at each end; i.e., the enlarged image
on the easel would measure 11x16% inches from a 1x1*4 inch nega-
tive but we will use only an area 11x14 in size.

Consulting our first table we find that the exposure should be
9 times that required for one test print or 90 seconds.

Consulting the second table we find that if an exposure at f :4.5
is made it need be only % that at f :6.3, so we can open our lens to
f :4J5 and expose 45 seconds.

Similarly if we have made an exposure of 30 seconds at f :6.3
and we wish to double the exposure without increasing the time, we
find from the second table that f :4.5 requires % the exposure of
f:6.3, so we open to f :4.5 and use the 30 second exposure, getting
the same result as 60 seconds at f :6.3 would give.

One other problem frequently occurring is that when we have
made an excellent print 8x10 in size we wish to repeat it on 11x14
without wasting paper.

Consulting our first table we find that an 8x12 print requires
20 times the exposure of a 1x1% and that an 11x16% requires 36
times the exposure of a 1x1%. The 11x16% inch print would then
require 36/20 or 9/5 the time required for the 8x12. An exposure
double the exposure given the 8x12 would be close enough. This
ratio will hold true regardless of the amount of the negative used
providing the larger print includes the same proportion of the
negative as the smaller print did.

172

Ruth Henry M. Lester

Elmar 90mm lens, % second at f:6.3. J)u Pont Superior Film, 2 Pbotofloods

173

Comparative Speed of Yarious Projection Papers

Another bit of information which each worker must determine
for himself, but which is invaluable, is the relative exposure required
for each brand of paper as compared with any others he may use.
This is particularly desirable if expensive papers are being used, all
preliminary work being done on the less expensive paper and the
final print being made at considerable saving.

Figures opposite each paper stand for UNITS of Exposure Time.

(UNITS: seconds, minutes or counts.)

These data are approximate only and should be used with caution as
papers vary greatly in their sensitivity to light:

Agfa Brovira Gevaert Novabrom

Soft 1 Vigorous 7

Medium l1^ Normal 3

Hard 3 Extra Vigorous 8

Extra Hard 6 Gevaert Gevalux 15

Dassonville 1% Eastman Kodak

Defender Velour P.M.C. Normal 1

Black Soft 2 « Medium 2

" Medium 3 « Contrast 3

" " Hard 5 News Bromide Soft 1

" Hard 6 « « Medium .. 1%

Veltura 25 « « Contrast.. 2%

Gevaert Novabrom Vitava Projection 10

Extra Soft 2 Illustrators' Special 20

Soft 2% Vitava Opal 20

It should be borne in mind that there is a definite relationship
between the exposure time given a print and the time of develop-
ment required to bring out as many details of the negative as possible.
Most of the developers used for papers are so compounded as' to
produce a fully developed image in one and a half to two minutes.
Prints developed for less than that will not show all details, while
those developed for longer are apt to appear flat. However, just as
in the case of negatives, a certain amount of latitude is available in
some papers, permitting longer exposures and shorter development
or shorter exposures with longer development. This latitude will
enable the worker, with skillful handling, to obtain a variety of
results from one paper. If the negative is very dense and contrasty,
a softer print with more details will result from longer exposure

174

Enlarging Papers

and shorter development, while a soft and flat negative will yield a
snappier print with underexposure and longer development.

Definite knowledge of how to obtain these results must be left
to the worker himself, who will fully succeed in the proper control
of Ms paper and developer provided lie will select one paper, one
developer and learn all there is to know about both.

Short Stop

After the print has been fully developed it should be immersed for a
few seconds (from 5 to 10) in a so-called short-stop bath. This bath is
indicated for two reasons. It instantly stops the developing- processes of the
print, and it neutralizes the alkalinity of the developer, preventing the
carrying over of traces of developer into the acid hypo fixing bath. This
neutralizing action of the short-stop bath is important because it imparts
longer life to the acid hypo fixing bath and a more uniform action of
same. If this acid rinse bath is used, the fixing bath will fix out almost
twice as many prints as it would if no short-stop bath were used.
One quart (one liter) of the short-stop bath will process about twenty
8 x 10 prints or their equivalent of smaller prints. Properly prepared, an
acid fixing bath (one quart) will fix out approximately thirty 8 x 10 prints
or their equivalent in other sizes if the short-stop bath is used between
development and fixation or about one-half that number of prints if only
an ordinary water rinse is used.

A short-stop bath is prepared by diluting one and a half ounces of
acetic acid (28%) with 32 ounces of water (or 48cc to one liter of water).
If 28% of acetic acid is not available same may be prepared from glacial
acetic acid (a much more economical way) by diluting three parts of glacial
acetic acid with eight parts of water. It should be remembered that only
a short rinse in this short-stop bath is required (from five to ten seconds)
while longer immersion (one minute or more) will degrade the tones of
most enlarging paper, will cause blisters and general disintegration of the
emulsion of the print.

Fixing

Fixation is of utmost importance, as upon its thoroughness depends in
a large measure the permanence of the photographic print. Preparation of
an acid fixing bath should be done as carefully as that of development.
Fixation is generally complete within ten to fifteen minutes, provided every
surface of the print has full access to the bath and that the prints do not
stick together. The prints are best kept moving in the fixing bath.

There are three ways of preparing an acid fixing bath: First, for the
workers who do not turn out great quantities of prints a very satisfactory
way of preparing hypo is by purchasing ready put up packages of powders,
which contain all necessary ingredients, and follow instructions on each box.

Second, for those who do more work and like to prepare their own,
the following formula is most satisfactory and generally used:

Water 64 ounces 2 liters

Hypo 16 " 480 grams

175

When thoroughly dissolved, add the entire quantity of the following:

Hardening- Solution Separately Prepared
Water (at about 125° F.) 5 ounces 160 cc
Sodium Sulphite (dry) 1 ounce 30 grains

Acetic Acid (28%) 3 ounces 96 cc

Potassium Alum 1 ounce 30 grams

Dissolve the sulphite completely before adding the acetic acid. After
the sulphite-acid solution has been mixed thoroughly, add the potassium
alum with constant stirring. When the alum is dissolved entirely, harden-
ing solution should be cooled after mixing and slowly added to the cool
hypo solution while stirring the latter rapidly.

The third method, for those who require large quantities of hypo to be
kept for considerable time, is to prepare an acid fixing bath by dissolving
two pounds of hypo in a gallon of water and keeping it in a well stoppered
bottle. Separately a stock hardener solution is prepared as follows:
Water (at about 125° F.) 56 ounces 1700 cc
Sodium Sulphite (dry) 8 " 240 grams

Acetic Acid (28%) 24 " 750 cc

Potassium Alum 8 " 240 grams

Cold water to make 1 gallon 4 liters

Dissolve the chemicals in the order given, following instructions
given for formula above.

The fixing bath is quickly made by adding one part of this stock hard-
ener to four parts of cool hypo solution.

Finally, a very effective and economical method of securing hypo for
prints is to provide a large bottle and to pour into it all the hypo that has
been used once and not more than twice for fixing of negatives. Such
hypo is good enough for prints and makes it more practical to use fresh
hypo for every film treated.

It would seem unnecessary to warn against the use of old worn out
baths, but somehow everybody seems to do it. Hypo, Acetic Acid, Alum
and Sodium Sulphite are cheap (even the water hasn't been so highly taxed
as some things as yet). Your time and effort in getting a print as you want
it are valued at your own price; a worn out bath can stain every print and
you won't know it until you turn the bright lights on. Don't take the
chance! Another suggestion, thirty seconds devoted to moving each print
about in the hypo when first brought over will insure even fixing and prevent
unaccountable rings, and other marks from appearing during any later
treatment. One more, when a bath becomes milky, either through use or
old age, throw it away.

Washing

Having brought a print to this point with success, one looks for-
ward to the prideful joy he will experience when showing it to friends
and then tosses it into a tray of water into which a dozen other prints
will be similarly tossed before the first is removed, supposedly com-
pletely washed. "With the water running full force a print cannoi
be thoroughly free of hypo if other prints have been continually
brought over from the hypo bath. Washing should continue for
at least a full hour after the last print has been brought over,
preferably rinsing each print as it is taken from the hypo, "Washing;

176

Enlarging Papers

cannot be stressed enough if permanency is desired, as any trace of
cliemical left in the paper will discolor or fade the print, perhaps
not in the first six months, but a well washed print will last for years.
Thoroughness of washing after fixing is just as important as
every other step in preparing a good print. A print insufficiently
washed will deteriorate just as a print insufficiently fixed. Tin*
water used for washing prints should not be colder than 65° nor
warmer than 75 to 80°. "Washing should be complete in an hour's
time if the prints are moved about and the water constantly changed.
The Eastman Kodak Company makes and sells an excellent tray
syphon which if used in accordance with instructions accompanying
it, makes a most ideal aid for thorough washing of prints. This device
is easily attached and is absolutely fool-proof and safe in its operation.

Hypo Test

It is highly advisable to apply a very simple hypo test to be sure that the
prints are completed washed.

The following Hypo Test Solution is recommended by the East-
man Kodak Company and is known as Formula HT-la:

Avoirdupois Metric

Potassium Permanganate 4 grains 0.3 gram

Sodium Hydroxide (Caustic Soda) ... 8 grains 0.6 gram

Water (distilled) to make 8 ounces 250.0 cc.

To make the test, take 4 ounces (125cc.) of distilled water in a
clear glass and add % dram (Ice.) of the permanganate-caustic
soda solution. Pour % ounce (15cc.) of this diluted solution into
a clean 1-ounce graduate. Then take six 4" x 5" prints or their
equivalent from the wash water and allow the water from them
to drip for 30 seconds into the % ounce of test solution. If a
small percentage of hypo is present the violet color will turn
orange in about 30 seconds and become colorless in about one
minute. In such case the prints should be further washed until
no color change is produced by the test which proves that the
hypo has been eliminated.

Drying

Drying the print offers very little difficulty if a few points are
remembered. Curling is due to uneven drying more than anything
else. If the surface water is not wiped oif , it will collect in pools
leaving, at times, dents in the print which, when finally dried out,
shows strain marks in the gelatin. A print carefully wiped dry with
a viscose sponge and then dried on cheese cloth, face down, will
have so little curl as to flatten of its own accord when filed away.
Even when dried face up on a blotter, the curl is not objectionable.
The Eastman Kodak Company produce a print drying roll con-

177

sisting of a long length of corrugated paper together with two similar
lengths of blotting paper, the one faced with a specially prepared
cloth to prevent sticking to the face of the print. The two lengths
of blotting paper and the corrugated paper are rolled over a card-
board tube, forming a roll approximately 10" in diameter. Prints to
be dried are laid between the blotters facing the cloth. The roll
may be placed before a fan or left standing. When the prints are
dry they will be found to have a backward curl, quickly becoming
flat when removed.

Ferrotyping

There are two types of tins available for f errotyping prints requiring
high gloss finish. The least expensive are black enamel tins. Slightly
more expensive but very practical are chromium plated tins. Either type
will produce excellent results indefinitely if they are well cared for. They
scratch easily and should be protected from rough handling, grit and dirt
They should be carefully washed with a wet chamois or viscose sponge
directly after use. When stored they should be interlined with line paper or
wax paper, placed face to face. Do not allow your chemicals or solutions
to remain on your ferrotyping tins for any length of time as they will eat
into the enamel eventually causing blisters and corrosion, thus rendering the
tins useless.

Ferrotyping to produce really glossy prints is not a difficult matter if
a few precautions are followed. Glass, coated with paraffin or beeswax has
been suggested from time to time but is never really successful. Ferrotype
tins are too cheap to consider such substitutes. The tin must be thoroughly
cleaned with a soft cloth and a few drops of benzene or hot water every
time any particle is noticed to be adhering from the last prints. The tin
should then be lubricated with a solution of paraffin in benzene (10 grains
of paraffin to 1 oz. of benzene, 1 gram to 50cc). A few drops of this solu-
tion rubbed evenly over the tin and then polished gently with a soft cloth
is sufficient; this need not be repeated unless it becomes necessary to clean
the tin with hot water or benzene to remove particles stuck to the tin.
Normally it suffices to polish the tin with a soft cloth each time it is used.
Only glossy paper, specially coated for ferrotyping during manufacture,
should be used. The print should be brought from the wash water, rinsed
under the tap, and without draining laid face down on the tin and squeezed
dry. Too much pressure may cause the prints to stick; not enough, and they
will not get good contact with the tin and will have an uneven gloss. Little
difficulty, however, will be experienced as the latitude is considerable. The
tins are then set aside to dry in any warm spot with a current of air, such
as a window. Drying should take several hours at least; artificial heating
is not good, causing sticking and uneven drying which leaves strain marks.
If, on the other hand the prints are left in a damp place, or sufficient air
is not allowed around them, such as setting one tin next to another
separated by only a fraction of an inch, the drying will proceed from the
edges in and a ring shaped strain mark will develop. When dry, the prints
fall off of their own accord or will peel off readily if a corner is loosened
with a knife. Brown stains sometimes appear on the surface of ferrotvped

178

Enlarging Papers

prints, due to insufficient rinsing of the print or the tin. A damp cloth will
wipe this dirt away without affecting the gloss. Insufficient washing will
leave hypo in the print which turns yellow and cannot be remedied. Grains
of dirt or bits of gelatine stuck to the tin produce little holes in the print
which cannot be remedied. Ferrotyping on glass produces a waxy looking
surface which is anything but desirable. Cleaning with benzene, soaking
and referrotyping on a tin will produce excellent results.

Toning

There are two relatively simple methods of sepia toning depending
for their action on the conversion of the silver image to silver sulphide.
By bleaching the regular bromide print in a solution of Potassium Ferri-
cyanide and then redeveloping the bleached image in Sodium Sulphide
very excellent sepia tones may be obtained. The bleaching solution will
keep indefinitely and is as follows:

Water (cold) 32 ounces I liter

Pot. Ferricyanide 200 grains 14 grams

Pot. Bromide 200 grains 14 grams

Liquid Ammonia 20 drops 20 drops

When prints have been fixed, wash thoroughly to remove any trace of
hypo; prints on rough surface papers should be thoroughly dried before
bleaching, others may be bleached without intermediate drying. Bleach
until the image is but faintly visible. Wash all the yellow stain away under
the tap and redevelop in the following:

Water 32 ounces 1 liter

Sodium Sulphide 200 grains 14 grams

Redevelopment takes but a minute, after which the print should be thor-
oughly washed and dried. To obtain Brown-Black tones do not bleach com-
pletely. Dilute the bleaching bath 5 to 1 to facilitate even bleaching and
rinse off when the image is about half bleached.

The second method depends on the action of alum on hypo to form the
sulphide. The bath is made up as follows:

Water 32 ounces 1 liter

Hypo 4 ounces 100 grams

Alum 1 ounce 30 grams

The above solution is milky in appearance and should not be filtered, but
before use it must be ripened to avoid bleaching the prints. Toning is done
between 90° and 115° F. taking from 30 to 60 minutes.

The bath may be ripened by toning three or four old discarded prints
or by the addition of the following:

Silver Nitrate 8 grains 0.5 grams

Common Salt 8 grains 0.5 grams

Water 2l/4 ounces 70 cc

Toning may also be carried out in the cold solution, taking from 6 to
24 hours. An excellent plan is to keep a bath in the dark room at all times
and tone all discarded prints as well as those which it is purposely planned
to tone. By using the cold solution the process is fool proof, toning being
even throughout the print if it is first moved about to insure even wetting.
The prints may be left in the bath almost indefinitely without harm. By
toning discarded prints, many unusual things will be discovered.

Those prints which it is planned to tone should be printed slightly
darker than is desired as the toned print is several shades lighter than the

179

black and white original. If the hypo alum bath is not ripened the first
few prints will lose their delicate details.

There are numerous other methods of toning to obtain different colors,
but their use is not recommended to the beginner. Many manufacturers
issue pamphlets, obtainable through their dealers, describing these processes.

Spotting

Miniature camera work requires great care and cleanliness in
every step of the process, including the storing of the negatives and
their handling during inspection or use. However, no matter how
much care is exercised, prints will show occasional dust spots and
more rarely, dark spots, due to pin holes or minute scratchings in
the film. The removal of the latter is difficult, being impossible on
glossy prints and requiring very delicate use of the retouching
knife on matt and semi-matt prints. Spotting the former is not so
difficult with a little experience.

The hardest part of spotting prints is to find a pencil, crayon
or paint which will match, the print not only in color but also in
gloss. Pencils are effective only on a matt or rough, surface where
the slight gloss of a pencil closely matches that of the paper. For
most papers with matt surfaces, the carbon type pencils, which have
almost no gloss at all, are very satisfactory. On the semi-matt papers
ordinary soft retouching pencils are often quite satisfactory. For
sepia toned prints on semi-matt surfaces, sepia crayons can be used.
Fine spotting brushes with Chinese India Ink are very satisfactory
if the tones of the print are real black, such, as obtained from con-
tact paper when very little bromide has been used in the developer.

For really good results on all kinds of papers, a medium such as
paint which is flexible both as to color and gloss is necessary. The,
one drawback to paint, however, is the fact that for single prints
or even to spot less than say half a dozen prints at one time, it is
necessary to go to considerable bother in preparation. Some spotting
colors are available on glazed paper cards but the most satisfactory
method is to obtain artist's water colors, coming in tiny trays. Three
colors are really necessary, lamp black — dull, blue black — dull, and
burnt sienna — slightly glossy. For mixture with the above to obtain
the necessary gloss a tube of Talen's blackish and another of Talen's
brownish should be obtained. The total cost of the above, together
with a good spotting brush, would be about two dollars and would
last for many years.

Using a small bit of opal glass for a palette, carry a bit of the
dull color on your wet finger to the glass. To this should be added

180

Willett

Albert Simmons
181

some of the glossy color, until, as mixed with the finger on the glass,
the color appears to be slightly more glossy than the print. Some
experimenting will be necessary before the right sheen can be recog-
nized, but it should always be remembered that the dull paints have
less sheen than has the roughest matt paper, with the possible excep-
tion of such special finishes as Gevalux. Moisten the brush with a
turning motion in a drop of water on the palette, wiping off any
excess water with the same turning motion on a bit of photographic
blotter, still turning the brush in the same direction, take up a bit
of the mixed color and apply to the print in very small dots. Do
not attempt to finish the job in one operation, keep the dots separated,
letting them dry while working on a different portion of the print
and then coming back, several times if necessary, to fill in the spaces
between the dots. If the brush is not too wet and if the minimum
amount of water has been used in mixing the colors, it will be found
that by very light strokes nice even dots can be made which will
not smear or vary appreciably in color when dry. The smallest pin
holes appearing in a print usually require about three of these fine
dots to be properly concealed. If it is attempted to put one large dot
in these holes, the paint will dry in a little lump which will usually
rub off after it has dried. In using an etching knife to remove dark
spots, such as are caused by pin holes in the negative, it will usually
be found most successful to carry the operation a shade beyond the
adjoining tones, spotting with the proper color so as to obtain the
right gloss, since on glossy prints any knife work leaves a matt
surface and on matt prints knife work leaves a semi-gloss surface.

Another method of spotting matt prints, particularly suitable
for portrait work, or where large areas are to be covered, such as
working in backgrounds or clouds, is the use of chalks. These can
be obtained in blocks from artists ' supply stores or can be prepared at
home from the filing obtained when sandpapering retouching pencils
to a fine point. The only things which must then be bought are
stumps and pumice powder (used by draughtsmen on tracing cloth
for making the ink hold and obtainable from most artists' supply
stores). Excellent stumps can be made at home after a little practice
by rolling lengths of paper on a diagonal so as to obtain different
sized points. However, soft chamois and paper stumps cost little.

The print is first rubbed lightly with pumice to eliminate any
possible grease and the chalk, mixed with a little pumice, is then
rubbed on and worked with a stump to the necessary shade. For

182

Enlarging Papers

large areas, such as working in backgrounds or clouds, a ball of
cotton dipped into the mixture of pumice and chalk is used to cover
the area, the larger stumps then being used to work in the shading
and detail. In working in backgrounds a soft eraser can be used to
break the outline in long slanting strokes, a soft bit of clean cotton
then being used to soften the edges of the breaks and smooth out the
outlines. Some experimenting and a considerable study of studio
portraits will be necessary before really good work of this sort can
be done. To fix the chalk to avoid rubbing, etc., provide a large tray
of water. The tray should be considerably larger than the print and
should contain about 2 inches of water, more if possible. Holding
the print by both ends, give it a considerable curve and in one move-
ment draw it into the water, to the bottom of the tray and out at
the other end of the tray. Allow the water to drain off one end and
without shifting the position of the print hang it up to dry. Streaks
will appear if the movement of the print through the water is jerky
or if the print is moved around while the water is draining off.

When Matte and Semi Matte Papers are used a light coating of
wax often lends a beautiful luster to the print. "Waxing prepara-
tions may be obtained from your dealer. In applying them it is best
to use a small pad of cheesecloth to apply a little wax over the entire
print, then quickly rubbing off the excess with a clean cloth. Some
preparations require considerable time to dry; others can be handled
within an hour. The bottle should give all necessary information.

Presentation of the Finished Prints

One phase of photography which is almost totally ignored by
the average worker, is the presentation of his print. Not that the
frame is required to appreciate the beauty of a picture, but it does
help considerably. The average album of snapshots is undoubtedly
the best illustration of the worst method of presenting prints. If the
prints are to be mounted in albums, considerable thought should be
given to the size of the prints, the widths of their borders, and the
color of the stock in comparison with the size and color of the album.
Prints in black and white do not show up effectively on buff or ivory
stock nor are they as effective in an album the pages of which are of
buff or have a brown tone. They should be mounted, preferably,
on white or gray. Similarly, buff prints or sepias look their best
against the background having brown or buff tones. The mounting
of the prints in, the album should be tasteful rather than convenient.
The use of tissue, black, brown or white, under the print and showing

183

a narrow edge, is very effective. After some experience, the amateur
with a taste for modern contrasts will learn to use tissues of such
striking colors as red or blue.

For prints to be shown separately, mountings on heavy stock
are to be recommended. The simplicity and taste which is shown in
the choice of the stock and the method of mounting will be the key-
note of its success, yet it is a relatively simple matter to prepare
such mountings.

Embossing Prints

The simplest of all is the embossed print. For this, it is neces-
sary to carefully plan the print so that no trimming of the picture
is necessary. Sufficient border is left to properly frame the finished
picture, somewhat more at the bottom than at the top and sides. A
piece of card is then chosen, about the same thickness as the stock
or slightly thicker; this is trimmed the same shape as the picture
but a trifle larger. If a heavy glass plate is available a light is
placed under it, the card just trimmed laid on that and the picture
placed face down over the card and adjusted to leave an equal border
around the pieturd. With an embossing tool, the back of a tooth
brush or knife handle, the stock is rubbed equally all around the
edge of the card, causing the picture area, when viewed from, the
face, to be sunk behind the border. Many variations will suggest
themselves to the imagination, such as beadings, double borders, etc.
The print thus embossed may then be trimmed to equalize the borders.
The edges may be roughened by laying the print on the table with
the edge out to the table edge and scraping with a sharp knife.

In cutting the card so as to make window mounts, cut from the
back and against a hard surface so as to leave a smooth edge. To
cut on an angle, lay a steel or other thin ruler under the knife, hold-
ing the knife firmly and keeping the blade of the knife and the nail
of the index finger firmly against the guide — thus maintaining a con-
stant angle.

The final step in mounting, particularly for Christmas cards, is
the book or folder. The print may simply be placed in the folder,
or a card mount nicely embossed, or again a window mount may be
prepared and the whole placed in the folder. The folder preferably
should be of lighter material than the card used as a mount in the
last two cases, although like everything else, this is really a matter
of taste and individuality. A tissue paper fly leaf may or may not
be inserted. The cover may have some design embossed into it or

1QA

Enlarging Papers

may be printed with a linoleum or wood block. Any number of
variations suggest themselves and much pleasure will be derived from
making individual mounts.

One word about pasting. Library paste, homemade paste and
any glue will do the job. Some contain products which will injure a
photograph, but most are quite satisfactory. However, for a neat
and convenient, as well as reliable job, nothing is as satisfactory as
dry mounting tissue. A hand iron, kept nicely warm, or if of the
automatic type, set at a low heat, is just right for mounting pictures
up to 11" by 14" and the thinnest mounts will lie flat.

Eubber cement is probably the best and the cleanest mountant.
It should be spread with a large brush over both the mount and the
print and allowed to dry for more than a half hour. The print
must then be carefully adjusted to guide marks previously made on
the mount, for once placed it will be impossible to move the print.
Any excess cement around the edges can be removed with a soft
cloth. Do not get rubber cement on waxed prints as it removes
the wax. When using paste glue or cement the mounted print
should be placed under light pressure for a short while before putting
in a press or under heavy pressure for final drying. When transfer-
ring from the light to the heavy pressure a careful inspection should
be made to be sure no paste or cement has oozed out at the edges of
the print.

Many advanced workers are using thin papers for paper nega-
tives,- a beautiful result can be obtained by printing on the thinnest
papers available and carefully mounting on medium weight mounts.
This is particularly satisfactory for Christmas cards. Thin papers
must be treated carefully to avoid air bells in the developer and hypo.

And so a little has been said regarding many things. Perhaps a
first reading has confused some or led others to believe that the
whole matter is unnecessarily involved. I hope, however, that in
some way many who have read this chapter will become more keenly
appreciative of the importance of printing as one of the major steps
in producing a photograph; far too little has been said to date
regarding this angle of photography, each newcomer apparently be-
ing expected to struggle along until somehow he succeeds in turning
out one or two good prints from each package of paper he buys.
If, as has been stressed several times before, the beginner will stick
to one paper, one developer, etc., until lie is turning out a fair aver-
age of good prints, he should find that lie has learned to do this
with very little waste of paper and time.

185

Fig. 118 A Dandelion Gone
to Seed. . .Photo by Wm. M.
Harlow

135mm Elmar lens, f:36, 5 sec-
onds, Panatomic. Sliding Copy
Attachment used.

Fig. 119 Sprouting Peas

186

J. M. Leonard

COPYING AND CLOSE-UP PHOTOGRAPHY

WILLARD D. MORGAN CHAPTER 9

Data Tables by Henry M. Lester
*

In ordinary use the Leiea cannot be adjusted for photographing
objects at distances less than 3y2 feet without the aid of special sup-
plementary front lenses or one of the copy attachments. Thus the
3^ foot mark becomes the dividing line or norm for the Leica user
who is interested in photographing large or small objects. Let us
step across the threshold of this 3% foot mark and explore the
wonders of the world of small objects. What a contrast! In the
large object field we were photographing people, buildings, moun-
tains, and even the moon or sun far out into the space of infinity.
Yet in the small object world there is a universe in itself to be
explored by the inquisitive mind. Here a book page may be copied
or a micro-organism photographed on the Leica negative with a
2,000 times magnification. A truly amazing contrast from infinity
to 2,000 times magnification. The user of a Leica can readily span
this gap.

Intensive work in photographing the large object world has been
carried on for nearly a century. However it has only been in recent
years that small object or micro photography has become an essen-
tial part of our daily living, mainly because of the important ad-
vances in camera design. The eye of the camera was made to peer
into the inner structure of the world. All the large hospitals and
educational institutions have elaborate photographic departments
equipped for the close-up micro photography of specimens which
are invaluable for future reference by the medical and teaching staff.
Police departments use the camera for close up photography just
as nimbly as they use their guns. Industrial firms keep constant
photographic records of their products which may be used for refer-
ence, sales, or advertising purposes. The visual education field is
an important user of close up or small object photography for pre-
senting thousands of different subjects on the projection screen or
by actual photographs to millions of students. Such examples show

187

us how Immense and likewise important the field of small object
photography has become. Let us now learn how to use our Leica
camera for this type of work.

Practically everyone who uses a camera has had the occasion to
make close-up photographs of objects. Such pictures may have been
more or less successful depending upon the camera and experience
of the operator. The copying possibilities of a camera should really
be looked upon as the visual note book which is indispensable for
keeping accurate records of any object, such as machine parts, draw-
ings, manuscripts, geological specimens, medical subjects, or small
magnified pictures of insects. In fact it may be said that anything
can be copied that can be illuminated adequately for photographic
purposes.

If you are a student the copy camera outfit can quickly be
applied for illustrating your biology note book, or possibly you may
need references from rare books which can not be removed from the
library. In the latter case the camera can be utilized perfectly and
at a minimum expense. The developed negatives may be placed in a
projector or enlarger and read directly from the projected image.

Importance of Small Object Photography

This chapter on Small Object Photography should be studied
carefully because it is the basis upon which other chapters have been
prepared. A thorough knowledge of the copying equipment and
methods will enable you to grasp a complete understanding of the
following chapters which are so closely related to the present chapter :

A. The Leica as an Ophthalmic Camera.

B. Miniature Camera for Miniature Monsters.

C. Making Leica Film and Glass Slides.

D. Dental Photography with the Leica.

E. Photomicrography with the Leica.

F. The Leica in Visual Education.

G. Historical Keseareh with a Leica.

Close up photography of small objects really has a field and technique
quite different from the usual type of photographic work which is prac-
ticed by everybody who can focus a camera and click the shutter. When
we start taking photographs of a butterfly, newspaper clipping, flower,
mineral specimen, or any small object, a number of special problems arise.

1. The camera requires additional equipment.

2. Focusing becomes more critical as depth of focus decreases.

3. Exposure factors change and are calculated according to the degree of
magnification required.

4. Proper illumination becomes an extremely important problem.

188

Copying

5. It is often necessary to use color filters in order to obtain certain re-
sults.

6. The Leica camera and auxiliary equipment must be mounted on a rigid
base, free from vibration.

7. The proper film must be selected for use with the various types of copy
work.

8. Even the specimens to be copied should be mounted or properly ar-
ranged in order to insure a perfect reproduction on the negative. As
the final picture will be reproduced in black and white, or monotone,
it is important to select objects which will produce the best contrasts
and details required.

As most of us are not equipped with spacious photographic studios
our camera equipment should be small, light, and easily portable.

Even the developing technique is of great importance for films made
of small objects.

Once the proper equipment has been assembled for any type of close
up photography there will be many interesting objects to photograph. In
fact you will begin to see a new world in miniature.

Accessories for Close Up Photography

There are a number of accessories provided for covering every
possible demand which may arise for the Leica user who wishes to
use his camera for copying. Each copy attachment will be indi-
vidually described in order to present the features of each one in
such a way that the Leica worker may easily make the proper choice
to fit any special requirement.

Sliding Focusing Copy Attachment

Shortly after the introduction of the Model C Leica with the
interchangeable lens feature in the Fall of 1930 I
started experimenting with the use of various ex-
tension tubes placed between the camera and lens.
These extension tubes actually take
the place of the familiar long exten-
sion bellows to be seen on the larger
view cameras. My results for this
type of close-up copy work were
very encouraging and I saw the pos-
sibility of developing a new field
for Leica users. Following the
work with the metal extension
tubes I designed the first Sliding
Focusing Copy Attachment which
has since been manufactured and
distributed to thousands of Leica **™J* f^fdy)
users during the last few years. sition for Copying

189-

Basically the Sliding Copy Attachment, also known as the Fuldy
Copy Attachment, consists of two metal plates, one for attaching to
the camera and the other for holding the lens and extension tubes.
On the part which holds the camera there is a ground glass with a
masked out area equal to the size of the Leica negative. This ground
glass screen is in exactly the same plane as the film in the Leica
camera. Therefore when the image of the object being photographed
is in sharp focus on the ground glass it will also be in perfect focus
when the camera is moved into the same position directly over the
lens.

The Fuldy Copy Attachment has been designed for use in any
position required for photographing either horizontal or vertical sub-
jects. A tilting top or Ball Jointed Tripod head may be used for
securing this attachment to a tripod for indoor or outdoor use. A
special bolt can be secured for inserting into the hole of the Sliding
Arm which is also used for holding the rod of the illuminating
bracket. "When this bolt is in position the Leica or the copy attach-
ment can easily be secured in a horizontal position for photographing
such objects as the human eye, maps on a wall, or mounted speci-
mens. In fact after a little experience with the Sliding Copy Attach-
ment it will be found that any photographic angle may be quickly
secured.

Around the focusing plate there is a clip mount for attaching the
special magnifier which is of value when obtaining extremely critical
focus. Once the Leica is attached to the sliding plate of the Fuldy
accessory it can readily be reloaded at any time without removing
from this plate. A Wire Release must be used for releasing the
shutter in order to avoid any possibility of jarring the camera at the
time of exposure.

Description of Sliding Copy Attachment Parts

The accompanying illustration gives complete information about the
various parts of the Fuldy Copy Attachment. This copy attachment is
adapted for use with the various Leica models which have the interchange-
able lens feature. Owners of the early Model A Leica can have their
cameras converted so that the lens will be detachable, for use on this at-
tachment as well as for the Leica enlars-er and

190

Copying

Fig. 121 Essential Parts of the Sliding: Focusing Copy Attachment

1. Light shield to prevent stray light from entering camera opening while
focusing.

2. Threaded opening for securing the attachment to a tripod, extension
arm of the reproduction stand, or the Sliding Arm for use with the
upright pillar of the Leica enlarger.

3. Dove-tail groove into which the sliding plate (No. 8) moves while focus-
ing and making exposures.

4. Stop for use when changing from focusing to photographing position.

5. Leica lens screwed into position.

6. Clamping ring for holding the Leica camera securely to the sliding
base plate.

7. Key for turning clamping ring (No. 6).

8. Sliding base plate for holding the Leica camera, focusing ground glass,
and also the magnifier.

9. Focusing ground glass in exact plane with the film in the camera.
There is also a place to attach the magnifier when necessary.

10. Space cut from the sliding plate (No. 8) to permit the Model F or G
Leica camera to fit properly.

The Fuldy Attachment in Use

The Fuldy device may be set up as follows:

A. Attached to the Sliding Arm which is secured to the upright column
used for the Leica enlargers.

B. Mounted on the Collapsible Reproduction Stand.

C. Secured to a ball jointed or tilting top tripod head which in turn is
attached to a firm support such as a tripod.

191

Before the set up is complete the subject to be copied must be placed
into position and properly illuminated. Finally the correct focus is deter-
mined by moving1 the camera close or away from the object. Fine focusing
is obtained by using the focusing mount on the lens, or in the case of the
50mm lenses the lens barrel is moved back and forth in its mount. Once
perfect focus has been secured on the ground glass the camera is slid into
position ready for making the exposure. Stop the lens down as far as
practical after focusing and before making the exposure.

When the regular 50mm Elmar lens is used on the Fuldy Attachment
directly without the use of additional extension tubes it is possible to
photograph any object which comes within the maximum area of 15 x 20
inches and a minimum area of 4 x 6 inches simply by moving the lens mount
in or out and setting the camera in the proper position. On account of the
sliding feature of the Fuldy Attachment it is not possible to collapse the
lens far enough for including greater areas than 15 x 20 inches without re-
sorting to a special adjustment which extends the usefulness of the attach-
ment up to any limits including infinity. To obtain such areas proceed as
follows:

1. Place a rubber ring1 (such as the ring supplied with the Micro Ibso
Attachment) around the barrel of the 50mm lens.

2. Slowly push the lens barrel into the mount until the image is sharply in
focus on the ground glass. The rubber ring will then be flush with
the base of the lens mount, and thus mark the exact position where the
lens is in focus. In this position the lens barrel projects into the at-
tachment and thus prevents the upper sliding plate from moving.

3. After exact focus has been secured pull out the lens barrel, slide the
camera into position, and push the lens barrel back to its proper posi-
tion now accurately marked by the thick rubber ring.

This method of securing photographs of larger areas is seldom required
because the majority of subjects copied are much smaller and may be
copied in the regular way with the Fuldy Copy Attachment.

The Extension Tubes

In order to secure proper focus at the higher magnifications it is
necessary to move the Leica lens away from the film plane. Instead of
using a cumbersome bellows similar to the larger view cameras for holding
the lens in proper position I designed the 12mm, 30mm, 60mm, and 90mm
metal extension tubes for this purpose. With such a set of tubes together
with one of the collapsible 50mm lenses, any combination can be secured
to obtain the proper magnification and focus upon an object which might
be as small as a pinhead. Such tubes are small and light and keep the
lens in a rigid position at all times.

When the Fuldy Attachment is used with th~ 30mm tube and the 50mm
lens natural size or 1:1 pictures may be made. By pushing the lens barrel
into its mount additional areas may be covered. The 60mm tube is very
useful for securing slightly higher magnifications and also for use when
the Fuldy Attachment is used with the microscope. An unusually long set
up of 'extension tubes may be seen in the arrangement for insect photog-
raphy illustrated in J. M. Leonard's chapter.

The introduction of the Sliding Focusing Attachment in connection
with extension tubes of various lengths greatly increased the Leica's use-
fulness. Every day new fields are being reported where the application
of these accessories was at first found useful and later became indis-
pensable.

192

1. Twig and buds of
sugar maple show-
Ing bud scales
and bud scars.

2. Flower bud of
flowering d o g -
wood.

3. Leaf bud of flow-
e r i n g dogwood
showing valvate
scales.

4. Naked bud of
wayfaring tree.

5. The leaf scar
covers the bud.

6. Stipule scars ap-
pearing as a line
encircling the
twig.

7. Twig and buds
of butternut show-
ing a leaf scar,
bundle scars, and
superposed buds.

8. Collateral buds.

9. Leaf scar and
stipule scars.

10. Pseudoterminal
bud and branch
stub of red mul-
berry.

11. Thorn.

12. Stipular spines of
black locust.

13. Pseudoterminal
bud and branch
scar of basswood.

: 11

Fig. 122. Twig and Bud Photographs by Wm. M. Harlow

During the Winter months the leafless trees in our forests or parks
have very reliable marks of identification on their very "finger-tips" or
twigs. Dr. Harlow uses the Sliding Focusing Copy Attachment for secur-
ing interesting close-up photographs of these buds. Here is a field of pho-
tography which is extremely interesting and many Leica users can apply
their knowledge of copying very successfully.

193

Most of the information concerning the use of these accessories was
available for the 50mm lenses because they are the most popularly used.
It will be found however that lenses of longer focal length are extremely
useful for certain types of work* In order to facilitate and simplify the
use of these accessories with any of the Leica lenses and tubes the Editors
now offer for the first time a new table and some basic formulas which
will enable the average worker to determine certain important factors for
the different lenses and extension tubes without resorting to tedious experi-
mental or mathematical work.

The table given on pages 198, 199 was computed for the 50mm lenses
(either Elmar, Hektor, or Summar). This table should be consulted not
only for information regarding the use of these three lenses, but also as
an example of information that can be obtained by the use of the few sim-
ple formulas which follow.

It should be noted that the figures contained in this table referring
to the depth of focus are based upon the diameter of the circle of confusion
being ,03mm (approximately 1/750 of an inch). This is the only part of
the table which is affected by the size of the circle of confusion. Should
a smaller circle of confusion be required, or a larger one be found suffi-
cient, the data given in the table should not be used, but other figures
computed with the aid of the formulas appended.

The 135 mm Lens Mount

Still another method of securing focus for objects at any distance up
to infinity, when using the Fuldy Attachment, is by using the special
135mm lens mount which is llmm shorter than the regular mount for this
lens. In other words this mount is made to compensate for the llmm dis-
placement of the lens in the Focusing Copy Attachment. (This mount may
be ordered through any Leica dealer in the United States.)

The 135mm lens is easily unscrewed from its standard mount and
placed in the shorter mount for use on the Fuldy Copy Attachment. With
this mount in place the copy attachment is excellent for use in taking
portraits or any other subject which can be focused upon the ground glass.

The special 135mm mount is supplied with a reducing ring for at-
taching the 50mm lenses. By using this set-up it is possible to secure fine
focusing simply by turning the focusing mount of the 135mm lens barrel.
Additional extension tubes can be attached when required to secure higher
magnifications.

INCH

Fig. 123 Latent Finger Print
on Black Rubber Surface . . .
Gray Finger Print Powder.
Photo by Ira Gullickson. Slid-
ing Copy Attachment, used
with 30mm tube

194

Copying

Use of Extension Tubes Directly on the Camera

Without Sliding Focusing Attachment

It is frequently desirable to use various Extension Tubes or
their combinations directly on the camera, without the use of the
Sliding Focusing Attachment. This is quite practicable. The tube
is simply screwed into the camera and the lens is screwed into the
tube. Such an arrangement sometimes can be used in lieu of auxil-
iary front lenses. The focusing is then done to scale. Great accuracy
is an absolute prerequisite of success.

The following table is given for this type of work.

It is based upon the diameter of Circle of Confusion of 0.03mm.

Since it is impossible to compose the picture on the film visually
it is recommended to use a plumb weight whenever this method is
employed. Special plumb-weights are available, but any plumb-
weight will be found to work as long as it will be made so that it will
drop in a line with the optical axis of the lens.

WORKING DISTANCE, RATIO OF MAGNIFICATION, DEPTH OF
FOCUS, EXPOSURE FACTORS AND FIELD OF COVERAGE FOR
EXTENSION TUBES USED DIRECTLY ON LEICA CAMERA
(without Sliding Focusing Attachment) with ALL 50mm Leica Lenses:

Elmar f :3.5 Hektor f :2.5 Summar f :2

Total
Length
in Milli-
meters

Extension
Tubes

Working
Distance
(from
object
to Lens)

in MM

Depth of Focus
at f/12.5
Nearest Farthest
points in focus

in Millimeters

Exposure
Factor
(Increase
in exposure)

(Times)

Approximate
Field
Covered

in MM

Ratio of
Reduction
or Magni-
fication

259

251

267

1.5x

96 X144

4:1

164

161.5

167

2.0x

54 X 81

2.25:1

133

131.3

134.7

2.5x

38 X 58

1.6:1

12+30

109

108.2

110

3.4x

29 X 43

1.2:1

91.6

92.7

4.8x

20 X 30

1:1.2

60+12

84.6

85.5

6.0x

16 X 24

1:1.5

77.7

78.4

7.75X

13 X 20

1:1.8

102

90+12

74.5

74.3

74.8

9.25x

12 X 18

1:2

120

90+30

70.8

71.2

11. 5x

10 X 15

1:2.4

142

90+30+12

68.8

69.2

14.75x

9 X 14

1:2.6

150

90+60

66.6

66.4

66.8

16.0x

8 X 12

1:3

162

90+60+12

65.5

65.4

65.7

IS.Ox

7.5 X 11

1:3.25

180

90+60+30

64.0

63.9

64.1

21.0x

6.7 X 10

1:3.6

192

90+60+30+12

63.0

62.9 ,

63.1

23.5x

6.25 X 9-35

1:3.85

lot;

Fig. 124 Photo of Herbarium Sheet by Carl B. Wolf. An example to
show the use of the Leica Copy Equipment in one particular photographic
subject.

•** :I^^^V'\*^^;¥vi^:m^\, o?~ *~

- *

Figr, 125 Writing Showing Shading Vari-
ations in Pen Pressure and Grain of
Paper. Elmar 50mm Lens with Focusing
Copy Attachment

Fig. 126 Copy of Typewriting. . . by Ira
Gullickson. Pica type, ruled square on
glass over typing. Fine detail shows type
and kind of paper. Printer's ink in dotted
line seen as being different from typing.
Fuldy Copy Attachment with Elmar 50mm
lens, 30 and 60mm tubes.

196

Copying

Exposure Factors

For ALL Extension Tubes When Used With Various Leica Lenses

and the Sliding Focusing Attachment

Tubes Lenses:

35mm

50mm

73mm

90min

105mm

135nim

llmm

1.75x

l.DX

1.33x

1.26x

1.21x

l.OSx

12mm

1.8x

1.54x

1.35x

1.28x

1.24x

1.09x

22mm

2.65x

2.1x

1.7x

1.5x

l,46x

1.35x

30mm

3.45x

2.55x

2.0x

1.78x

1.65x

1.5x

60mm

7.5x

4.8x

3.3x

2.75x

2.45x

2.1x

90mm

12.8x

7.8x

5.0x

4.0x

3.45x

2.75x

* Special Focusing
Tube:

Shortest
Adjustment:
81mm

ll.Ox

6.8x

4.5x

3.6x

3.1x

2.55x

* Special Focusing
Tube:

Longest
Adjustment:
97mm

14.2x

8.6x

5.4x

4.3x

3.7x

2.95x

* This Extension tube was originally designed to permit the use of the 135mm lenses
in connection with the Sliding Focusing Attachment. It is actually a sawed-off 135mm
lens mount. The 135mm lens is screwed into this tube. In this form it can be used
on the Sliding Focusing Attachment even at infinity: the calibrations having been retained.

A special threaded collar is supplied with this tube which permits the use of any
other Leica lens. However lenses other than 135mm cannot be used for infinity focus in
connection with this tube. These lenses are used merely for extreme magnifications, in
which case this tube becomes a convenient adjustable extension tube.

This table of Exposure Factors for all tubes and all Leica Lenses will
be found useful for ascertaining* the correct exposure factors:

1. when using" extension tubes directly on the camera (without
Sliding Focusing Attachment), interposing them between the
camera and any lens.

2. when using various extension tubes or their combinations _ in
connection with Sliding Focusing Attachments and any Leica
Lenses.

For the purpose of exposure factors the Sliding Focusing Attachment is
considered just as any other tube of llmm length. Every tube, depending
on its length, has its own exposure factor, which is constant for every lens.

197

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Formulas

1. L — = Diameter of lens

f
D2

2. T = = Exposure factor (increase of exposure)

Fa
0 B — F

3. — = = Ratio of reduction (As a function of the object

IF or magnification distance)

0 F

— = — Ratio of reduction (As a function of the image

IF or magnification distance)

4. F2=(D — F) . (B — F) = (Relation between focal length, object

and image distance)

D . JF
B = = Working distance of object to lens

D — F

B . F
D = = Distance of image to lens

B — F

5. Depth of focus at a given diameter of Circle of Confusion:

L . B . F

A = = Nearest point in focus

(L . F) +C(B— F)
L . B . F

Z = = Farthest point in focus

(L . F) — C(B— - F)

Explanation of Symbols

M — Ratio of Magnification
R — Ratio of Reduction

0 — Size of Object (linear dimensions)

1 — Size of Image on film (linear dimensions)
B* — Distance of Object to the Lens

D* — Distance of Image to Lens
F* — Focal Length of Lens
f — Stop of diaphragm

T — Exposure Factor (increase of exposure)
C* — Diameter of Circle of Confusion
L* — Diameter of Lens

A* — Nearest point in focus when lens is focused for B.
Z* — Farthest point in focus when lens is focused for B.

* It is important to express all units of length in the same system, either metric or linear
(inches) .

Practiced Applications
1. Diameter of Lens :

(Focal Length)

L = or

f (Lens Stop(f))

Example:

What is the diameter of the aperture of a 50mm lens when it is
stopped down to f:12.5?

L r= = 4mm.

12.5

200

Copying

2. Exposure Factor:

Increase of Exposure T = •

(Distance from lens
to film plane)2

F2 (Focal length)2

Example:

What is the exposure factor for a 90mm tube when used directly
on the camera in connection with a 90mm lens?

[90mni (tube) + 90mm lens]2
Distance from lens to film plane

180 :

32.400

90 :

= 4x

90 2 81.00

3. Eatio of Reduction or Magnification :

Distance from Object to Lens
Size of Object O B — F less Focal length of Lens

Focal length of Lens

Size of Image
Example:

Ratio of Reduction of an object 900mm from a 35mm lens:
900—35 865

or:

Focal length of lens

say 25 -f- 1

D— F

Distance from Lens
to Film Plane — minus
focal length of lens
Example:

What is the ratio of Magnification obtained when using 60 and
90mm extension tubes in connection with a 73mm lens (tubes
directly on the camera — no S. F. A.)?

[60 + 90 + 73 (lens)] = D = 223
F 73 73 1

= = = or 1 -T- 2

D— F 223—73 150 2.06

Fig. 127 Copy of Old Mining Shares... by Willard D. Morgan. Focusing
Copy Attachment used with Elmar 50mm lens

201

4. Distance from Lens to Object or (B)

" Lens to Film Plane (D)
(knowing one how to find the other)

Basic Formula: F = (D— F) . (B— F)
D X F B X F

B = D =

D — F B — . F

Examples:

What is the distance at which the object is to be placed when a
60mm tube and S. F. A. are used with a IS 5mm lens?

(135 + 60 + 11) X 135

B =

(135 + 60 + 11) — 135
206 X 135 27810

= 392mm

206 — 135 71

What Extension tubes are to be used when a 50mm lens is avail-
able and the object is 97mm from the lens?

97 X 50 4850

D = = = 103mm 103mm — 50mm lens = 53mm

97 _ 50 47

or 53mm = llmm (S. F. A.) + 12mm (tube) + 30mm (tube)

5. Depth of Focus :

The depth of focus for any lens at any opening or distance depends
on the diameter of the Circle of Confusion. In all standard Leica
formulas the diameter of the Circle of Confusion is taken to be
C = 0.03mm

L X B X F
Nearest point in focus: A =

(LXF)+C(B — F)

L X B X F

Farthest point in focus : Z =: -

(L X F) — C (B — F)

Example:

What is the depth of focus of a 90mm lens at Stop F: 9, focused
upon an object 5 'meters away, assuming the size of the C. of C.
to be 0,01mm?

= 10mm; B == 5000mm C = 0.01

10 X 5000 X 90 4,500,000

A == - • = - — = 4750mm
(10 X 90) + .01 (5000 — 90) 900 + 49.10

10 X 5000 X 90 4,500,000

Z = -- = -- = 5300mm
(10 X 90) — .01 (5000 — 90) 900 — 49.10

Depth of focus will result in everything being in sharp focus at
from 4.75 meters to 5.30 meters.

202

Copying

Avoiding Vibration During Copying

Usually most close-up copy work requires time exposures ranging1 from
3/4 second up to 5 minutes or even more. During such exposures there must
be no vibration in the equipment to cause a blurred image on the negative.
In order to avoid vibrations the following points should be observed.

1. Use a rigid support for copying equipment.

2. Release shutter with a Wire Cable Release.

3. In case you are working in a building which transmits the
annoying vibrations of passing trains, trucks, or a subway, a
sponge rubber mat might be placed under the baseboard of the
copying attachment in order to absorb the motion.

4. When all the extension tubes are in use have a support or clamp
to hold the combination rigid.

5. When vibrations cannot be avoided use more illumination on the
object, a larger diaphragm stop, fast film, and make fast
exposures.

Focusing

As the camera lens is placed closer to the object the focusing becomes
more critical. Naturally without perfect focus the object will be reproduced
on the negative as a slight or even complete blur. With the Leica camera
there are three methods of obtaining proper focus.

1. By actual focusing upon a ground glass in the Sliding Copy
Attachments.

2. By measurement and the use of the printed tables supplied for
the purpose.

3. By using the fixed focus attachments such as the Bemar, Belun,
Besal, etc.

Ground glass focusing is recommended in the majority of cases because
it is so easy to actually see the object projected upon the glass surface which
is in the same plane as the film in the camera. A special 5x magnifier is
of additional help when determining exact focus with the Sliding Focusing
Copy Attachment. In case there is too much stray light falling upon the
ground glass, when the magnifier is not in use, take a piece of black paper
about 4x6 inches in size and wrap this around the ground glass mount. Use
a rubber band to hold the paper shade in position around the base. You will
now have a paper tube which will keep out any stray light. When the
•magnifier is in position this paper tube is not required.

The ground glass of the Focusing Copy Attachment looks grainy when
examined with the aid of the 5x magnifying glass. Considerable improve-
ment of the clearness of the image is obtained by applying a drop of oil
(cocoanut oil is very good) to the ground surface of the glass. Rub the oil
in gently and evenly, moving the finger first in one direction, and then at
right angles to it. This method will eliminate the graininess considerably
and increase the luminosity of the image, permitting better focusing.

Critical Focusing and the Special 30x Magnifying Glass

A special 30x magnifier is available to secure critical focus for those
who require the utmost precision and accuracy. This magnifier consists of
a small eyepiece equipped with a tiny lens of the microscope ocular type
and Quality. The lens with its mount slides in a collar which fits into the
half-rim clip on the ground glass of the Focusing Copy Attachment. This
magnifier cannot be used with the regular ground glass supplied with the

203

Fuldy Copy Attachment, be It ever so fine-grained. It would only magnify
the grain 30 times, but would not resolve the details of the image focused
upon the surface.

A special ground glass is available for use with this 30x magnifier.
It has a narrow strip of clear glass running across the center of the disc.
This clear strip is about 3mm wide. A millimeter scale is engraved in
finest hairlines upon the ground side of the glass disc, which corresponds to
the film plane in the Leica camera. The scale starts with 0 in the center
of. the disc and continues to the right and to the left of the 0 in millimeter
markings.

The magnifier is placed upon the Copy Attachment just like the regular
5x magnifier. The eyepiece is then moved in or out until the scale en-
graved upon the glass appears in perfect focus, sharp and clear. Then the
object or the camera is moved until the small portion of the object seen
through the magnifier appears in sharp focus. It will be found that the
image is clear and brilliant and permits the finest hairline adjustment.

This 30x magnifier works upon the principle of picking up the mag-
nified image of the object from the air. The focal point of the lens of this
magnifier is so critical, that if the image is not exactly in the film plane, it
will appear unsharp until corrected. The focusing should be done with the
lens of the camera open enough to permit sufficient illumination to enter for
easy focusing. After correct focus has been secured, reduce the lens dia-
phragm to the desired stop.

Coarse focusing, or the preliminary work in bringing the object into
fairly accurate focus upon, the ground glass, is secured by placing the
camera closer or farther away from the object. In doing this the Sliding
Arm to which the camera and Copy Attachment are secured is raised or
lowered on the metal upright bar which supports the equipment. In case
the camera is in the horizontal position mounted on the Sliding Arm or on
a tripod it is only necessary to move either the object or the camera closer
or farther away until sharp focus is secured.

When using a 50mm dens, fine focusing can be secured by turning the
lens mount or by slowly pushing the lens barrel in or out of the mount.
If the 90mm or any other lens besides the 50mm lenses are used the fine
focusing is easily secured by slowly turning the focusing mount on each lens
until sharp focus is secured.

When working with small objects a convenient stage or mount can be
made with an adjustable rack and pinion arrangement similar to the stage
of a microscope. Sometimes such a stage can be picked up in a second
hand store for only a few dollars; it makes a perfect platform for adjusting
small objects. Such a stage is fully described in the chapter by J. M.
Leonard on photographing insects.

Focusing by Measurement

When the Leiea is to be used without the aid of additional copy at-
tachments accurate focusing may be secured by referring to the special
booklet of tables for the Front Lenses, which is available free for any
Leica owners who use the Front Lenses in copying. This booklet of tables
gives the exact distance between the object and the film of the camera (not
the lens), the exact area covered by either one of the three supplementary
Front Lenses used, and also the depth of focus at the various diaphragm
stops.

When using the Leica with the Front Lenses it is necessary to have
the camera secured to the Sliding Arm or to a tripod or any other fixed
support, in order to keep the camera perfectly rigid.

204

Copying

Still another method of focusing by measurement is with the use of
the various Extension Tubes directly on the camera. When these tubes are
used singly or in combination it is not necessary to use the three Front
Lenses already mentioned. The Extension Tubes will enable you to use the
Leica at closer distances. For those who wish to use the Leica for copying
without the use of any copy attachment, a measurement table for use with
the Extension Tubes screwed directly into the camera has been prepared by
Mr. Lester. The Single Exposure Leica, described in the first chapter, can
be used very successfully for testing these fixed distances.

A special copying baseboard can easily be prepared to include the
various areas given in the table by marking out the rectangular areas in
ink or cut lines in the wood. Each rectangle should have figures giving
the area and also the Extension Tube and lens setting required to secure
perfect focus. Such a ruled board will be of great convenience for use
where many pictures are to be made of objects which are fairly uniform in
size.
Stopping Down the Lens

All copying should be done with the lens stopped down to f:6.3 or
smaller if possible. As the lens is stopped down the depth of focus in-
creases, thus insuring perfect focus at all times even if a slight miscalcula-
tion has been made when securing the original focus. When working with
high magnifications the lens should always be stopped down to f :12.5. A
special diaphragm Attachment Ring is available for use with the Hektor
and Elmar 50mm lenses, in order to adjust the diaphragm with side cali-
brations and thus avoid the necessity of standing on one's head to read the
settings on the face of the lens in case it is pointing; down toward an
object.

Fig. 128 Sea Urchin (Original Specimen 1% inches diameter). Series of
Four Pictures by Willard D. Morgan

Photographs made with Focusing Copy Attachment and various extension tubes to secure
different magnifications. Highest magnification made with a 21 cm tube extension.

205

Fixed Focusing

The various fixed focus attachments such as the Belun, Behoo, and
Bazoo are of value for certain uses and when only a few areas are to be
covered. The Belun attachment is permanently in focus for making; pictures
the exact size of the Leica negative or a 1:1 ratio. The Behoo and Bazoo
have extension legs with markings for special settings and areas covered.
Complete information about these attachments will be found in a special
booklet from the Leitz Company.

Securing Proper Illumination

The importance of proper illumination of objects to be* photo-
graphed at close range cannot be over-emphasized. Objects can be
flooded with strong light until they become flat, lifeless, and washed-
out reproductions on the negative. However with the proper type
of lighting the very same objects will take on a richness of tone
value which makes the final picture strong and at the same time a
perfect reproduction of the original.

One of the first methods of checking proper lighting is by per-
sonal observation. Side, top, or back lights may be adjusted at
various distances from the object, diffusion screens can be used to
soften strong direct light rays, high 01? low power bulbs should be
used when necessary. In some cases it may even be necessary to set
up one or more flash bulbs for making the picture. In most cases the
lights can be adjusted visually.

The best way to check the intensity of the illumination over an
object such as a manuscript page, is by using an exposure meter.
When in doubt about the proper balancing of the lights this meter
provides a rapid means of cheeking.

For the majority of objects the ordinary side lighting with the
lights set at a 45° angle is sufficient. One or two lights are placed on
each side, depending upon the size of the object. When these lights
are placed at a 45° angle the strong light rays illuminate the area to
be photographed without causing back reflections which would ruin
the picture, or at least make it fall short of becoming a perfectly
illuminated reproduction.

A convenient lighting set-up consists of two ordinary desk lamps
with reflectors. Two frosted 75-watt bulbs are sufficient for illumi-
nating all areas up to 12 x 16 inches. Beyond -this area use four or
more lamps as required. Even such a rule may not hold for every
set-up, because it is possible to use two photo-flood lamps or two 500-
watt lamps in reflectors and evenly illuminate greater areas. If you
have a Kodalite, Solite, or similar lighting outfits they can be used
very successfully for copying. Usually the high power bulbs must

206

Copying

be replaced with globes of lower light intensity in order to avoid over-
illumination.

It is also possible to nse normal daylight when convenient, al-
though artificial lighting is more constant and easier to control.
Sometimes when copying in libraries it is not possible to carry in
extra equipment such as lights. Here is where it is necessary to use
natural daylight. When photographing under such conditions the
full illumination from a window is sufficient. Avoid any cross light-
ing from other windows which may cast shadows or otherwise cause
uneven illumination.

Strong lights are useful when photographing moving subjects
where short exposures are required. In some cases the strong lights
may cause too much heat or otherwise disturb the subjects. To avoid
this the focusing may be done with a small light, then when the ex-
posure is to be made the full illumination is snapped on just before
the shutter is released. It may also be advisable to use stronger
lights when heavy color correction filters are used, thus reducing long
exposures.

Lighting Medical Specimens

Macro photography of gross specimens is a term often heard
when referring to the copying of medical objects such as bone sec-
tions, animal or human organs, or sections of tissues. Here is where
a knowledge of lighting is of special importance in order to obtain
good detail in the objects and also avoid glistening high lights or bad
reflections. In some cases the objects can be placed under water in
a large glass specimen jar, with the light directed from the sides.
Annoying reflections are thus avoided.

When a medical or any other subject is to be reproduced with
a plain white background there are three ways to do this.

1. Make the photographs and then opaque the negative by painting
around the object with opaque paint.

2. By using a white surface as a background for the object.

3. Produce a strong back lighting through an opal or ground glass.
Such a backlight will overexpose the background around the ob-
ject. The specimen is illuminated from the top in the usual way.
When the paper enlargement is made from this negative the
background will reproduce perfectly white if the exposure is made
for the object only. •

One of the most useful accessories for copy work is an illuminated
light box. With such a box the under or back lighting is easily
controlled, because the lights may be switched on for only part of

207

the time while the exposure is being made for the specimen mounted
on top of the ground glass. Such a lighting also helps to eliminate
unnecessary shadows when necessary. The top lights are used for
illuminating the object.

When a jet black background is required for a light object It
may be obtained by using a red glass, or celluloid, or paper, in the
illuminated box providing positive or orthochromatic film is used
in the camera. The red does not register on this film, therefore when
the finished enlargement is made a rich black is secured for the
background. Black paper or cloth may also be used for a similar
purpose.

Still another lighting set-up which produces a white background
without shadows can be prepared by mounting a clear pane of glass
about six inches or more above a plain white surface which is strongly
illuminated. By arranging the top lights at the proper angles the
shadows are cast out of photographing range while the illuminated
white surface produces an even background. This arrangement is of
value for photographing many objects besides medical specimens.

Fig. 129 Focusing
Copy Attachment Set-
up with Illuminated
Light Box for Copy-
ing X-rays, and Ob-
jects which Require
an Illuminated Back-
ground

208

Copying

Exposure Time in Copying

As the camera is placed closer to objects and the lens Is separated
farther from the film plane, the relative exposure time increases. Con-
sequently^ the values of the diaphragm stops vary according to the degree
of reduction or magnification. For example, when photographing objects
in actual size on the Leica negative the diaphragm of the 50mm lens will
be lOOmni from the film plane. In other words, when photographing objects
actual size on the Leica negative the distance between the nodal plane of
the lens and the film must be twice as great as the focal length of the
lens. With such varying conditions the actual value of the stop changes,
with the resulting changes in exposures. Once the correct exposure for a
given distance has been determined the exact factors for exposures at dif-
ferent settings may easily be determined by referring to the tables.

The following six points must be observed before determining the
exact exposure time:

1. Intensity of the light used.

2. Diaphragm stop to be used.
3'. Speed of the film.

4. Multiplying factors of any filters used.

5. Character of the object to be copied, which may be dark or light, rough
or smooth.

6. The distance between the lens and the film, which determines the ex-
posure factor for reduction or enlargement as given on page 198.

When photo graphing very small objects it will be found that it is dif-
ficult if not impossible to get a reading on the exposure meter, which
will be correct. This is due to the fact that the average meter usually
covers a much greater field than that occupied by the object. It will be
found helpful to get a piece of paper of about 5x7 inches or some other
material of a brightness or color similar to that of the average color or
brightness of the object and get a reading on that by placing it approxi-
mately in the plane of the object with relation to the light source. In the
case of insects or similar small objects it will be found most expedient to
color a piece of paper with water colors, giving it the average tint of the
texture of the insect.

The most accurate method of determining exposures when copying1 is
to make actual test pictures with different exposure times. A short length
of film may be placed in the Leica magazine and exposed under varying,
lighting, filter, diaphragm, and magnification or reduction conditions. De-
velop this film the proper time and then study the results and determine
the exact exposures to be given on the next roll of film which will be ex-
posed under the correct requirements.

Even a single exposure can be made on a short piece of film inserted
directly into the Leica after the Film Magazine and Take-Up Spool have
been removed. To do this, cut a piece of film approximately four inches
in length and insert directly into the camera back of the shutter. Press
one end down ahead of the other to avoid catching the film edge on the
lower metal frame which determines the margin along one side of the
negative. Try loading in daylight first, the exact position of the film
will be quickly seen if the focal plane shutter is set at Time and held open.
As 35mm film is inexpensive this method of testing exposures will be a real
time saver and also help' produce perfectly exposed negatives when the
good roll of film is used.

209

The Single Exposure Leica, described in the first chapter, can also be
used for making single negative tests. In addition to this camera there
is a convenient single exposure film holder for use directly in the regular
Leica camera.

Always keep accurate written records of exposures and notes about
filters, diaphragm stops, illumination, etc., when copying. After each roll
of film is developed, mark the perfect exposures in your record. Then
after a number of rolls have been exposed and recorded a final master
exposure table should be made for future reference.

Films Used in Copying

When selecting a film for copy work it is very important to have
a thorough understanding about the various film emulsions and just
what to expect from each one used. You may have attempted to
copy a book page or an article from your daily newspaper with one
of the fast panchromatic films and then wondered why the finished
negative looked flat without much contrast after development. Or
you may have copied an original photograph with a slow positive
film and wondered why some of the shadows disappeared and Tbe-
came black blotches in the negative or final enlargement.

Films for copy work may be roughly divided into four main
classes as follows:

1. Slow positive films.

2. Slow panchromatic films such as Micropan, Panatomic, Finopan,
Perpantic.

3. Orthochromatic films.

4. Fast Panchromatic films.

Positive film is contrasty and has an extremely fine grain emulsion.
This film obtains its name from the fact that it is used in the motion
picture industry for making positive prints from original negatives
for projection. Likewise this film is best for making positive prints
for projection in the Leica projectors. As positive film is not sensi-
tive to any color except blue and violet, it should not be used when
copying colored objects when correction filters are to be used. Use
Dupont Micropan for this purpose.

Use positive film for copying . . . printed matter such as books, news-
papers, charts, maps, line drawings, and objects which may require extreme
contrast in the final negative and enlargement. As positive film is not
sensitive to red this color will not register and thus there will be a clear
portion on the negative which prints black when enlarged. This film char-
acteristic can be put to excellent use when copying maps with red and
black lines, stamps printed in various red shades, or any other subjects
where the red lines should appear black in the finished paper reproduction.
A filter is not required for this type of work, just use the positive film for
making the negatives in the Leica, and make the exposures in the usual
way.

210

Copying

Use the slow panchromatic films such as Micropari for copying . , .
multi-colored printed matter, blue prints, or whenever correction filters
are to be used for obtaining special effects or more contrasty results.
For example a snappy black and white reproduction may be required from
an old newspaper yellowed with age. How can we obtain the proper re-
sults? To do this simply use Micropan film with a number II or III
yellow filter. In case still more contrast is required use a Wratten G or
even a light red (A) filter.

When copying1 a miscellaneous collection of subjects which may re-
quire some color correction along with others which do not require any
Micropan film is recommended as the most practical film for all around
use. This film can be used without filters for the ordinary black and
white copying.

Use the orthochromatic films for copying . . . original photographs
and objects where a better gradation of values must be secured in the
final reproduction. The orthochromatic films are fine grained and are not
as contrasty as the positive emulsions. In case positive film is not avail-
able it is possible to use one of the orthochromatic films for copying printed
matter and secure pretty good results, provided a contrast developer is
used. The Perutz Fine Grain Film is very good for this type of work
while the Agfa Plenachrome, Gevaert Superchcrome, and others can also
be used.

Use the fast panchromatic films for copying . . . paintings, moving
objects which require fast films, and any subjects which require color cor-
rection filters and short exposures at the same time. This film gives more
latitude, or in other words there is more gradation of values between the
highlights and shadows, this is of special value when copying paintings
which require faithful reproduction of the delicate color gradations.

Developing Films in Copy Work

Copy films are developed according to the results required just as
the proper film is selected for obtaining definite results. The usual tech-
nique which is fully explained in the chapter on developing applies equally
well to the processing of copy films. The only important variation conies
when developing the positive or the Micropan films where greater contrast
is required and development can be prolonged if necessary.

After printed matter or similar subjects have been copied on posi-
tive film one of the developers to use in finishing the negative is the East-
man D-ll solution which is mixed as follows:

Contrast Developer (D-ll)

Water (about 125° F.) 16 ounces 500 cc

Elon (Metol, Pictol, etc.) 15 grains 1 gram

Sodium Sulphite 2l/2 ounces 75 grams

Hydroquinone 130 grains 9 grams

Potassium Carbonate 'or Sodium Carbonate.. 360 grains 25 grams

Potassium Bromide 70 grains 5 grams

Cold water to make 32 ounces 1 liter

This fornrala used at 65° will give very good contrast in five minutes. When less con-
trast is desired, the developer should be diluted with an eq.ua! volume of water.

Development of the positive film should be carried out for the full
time. If the negative becomes too dense during this developing time it
means that too much exposure has been given when copying the original
subject. Only the finest negatives result from perfect exposures and com-
plete development. Of course one can watch the development of positive

211

film under a red safelight and slightly underdevelop the film if it is seen
that the exposures were too heavy. However the finished enlargements
from such negatives will not have the snappy quality which can be secured
by full development of a perfectly exposed negative.

In case extremely contrasty results are required on positive film a
caustic developer such as the Eastman D-9 will produce the correct results.

Caustic Process Developer (D-9)

Stock Solution A

Water (about 125° F.) 16 ounces 500 cc

Sodium Bisulphite % ounce 22 1/2 grams

Hydroquinone % ounce 22 1/2 grams

Potassium Bromide % ounce 22i/2 grams

Cold water to make 32 ounces 1 liter

Stock Solution B

Cold water 32 ounces 1 liter

Sodium Hydroxide (Caustic
Soda) 1% ounces 52 l/z grams

Use equal parts of A and B and develop about three minutes at 65° F.
Cold water should always be used when dissolving Caustic Soda because
considerable heat is evolved. Solution A should be stirred thoroughly
when the caustic alkali is added, otherwise the heavy caustic solution will
sink to the bottom.

This developer oxidizes quite rapidly and cannot be used over again
after the first developing. Therefore it is best to make several short test

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An Example to Show How the Copy Equipment can be Used for Saving
Considerable Time in Copying all Types of Eecords.

212

Fig. 131 Orange Stamp with Bla k Sur-
charge.. .Green Filter used to Giv Better
Black and White Contrast.

Fig. 132 Same Stamp as Fig. 131. Red
,(F) Filter Used to Absorb Orange Color
:»f Original Stamp, Permitting only Black
.Surcharge to Register.

Fig. 133 Genuine Stamp. Note the Clear
Design of this Stamp as Compared to the
Forgery Shown in Fig. 136.

Fig. 134 Detail of Genuine Stamp. Note
Clear Detail and Individual Parts which
Differ From Forged Stamp Shown in Fig.
135. The Second Ray to the Left of the
Sprout Almost Touches the Ground.

Fig. 135 Detail of Forged Stamp. Note

that the printing is not as Clear as the

Genuine. The Second Ray to the Left of

the Sprout Coming Out of the Ground is Fig. 136 Forged Stamp. A recent at-

Farther Away from the Ground. tempt to copy original Latvia Stamp.

Photographs made by Willard D. Morgan... using Focusing Copy
Attachment with 3 cm Extension Tube for full size stamps and 9 cm
tube for magnifications.

213

strips or even single negatives of the copy material and develop in a small
tray in order to determine the exact exposures before putting through the
full Leica film roll. Two rolls of positive film can be wound into the
Correx developing tank back to back and developed at one time if neces-
sary, if the operator has sufficient skill in handling film in this manner.

Filters Used in Copying

For most copy work only two or three filters will be required.
Even then a considerable amount of copying may be done without
filters. The chapter on filters will give complete information; how-
ever a few examples where filters may be used with panchromatic
films in copying may be tabulated as follows :

1. Wratten G filter . . . used for copying printed matter on yellowed
paper in order to produce a clear black and white reproduction.

2. Yellow number II or III filters . . . when copying paintings to secure
proper balance of color values in the black and white reproduction.
Colored maps may require one of these filters to bring out the proper
legibility. For example the names of cities may be printed in black
over a light red or orange background. With ordinary positive film
the color would turn dark and the contrast would not be sufficient. How-
ever, by using the yellow filter the "background is kept lighter so that
the names are readable, and yet there is a suggestion of the shaded
area. In case the red background is to be eliminated entirely use one of
the red filters.

3. Wratten A (red) or similar filters . . . excellent for use when copying
blue prints to make the blue background reproduce black on the final
enlargement. Blue or violet typewriting reproduces black when the red
filter is used. This filter may be used in many ways for securing spe-
cial results. For example the red design of a postage stamp will dis-
appear entirely when this filter is used, thus leaving a black surcharge
in bold relief for special study.

The tri-color set of filters, Wratten A (red), B (green), and C5
(blue), is very useful for securing over corrected negatives when
certain results are to be obtained. When the colored object is viewed
through a filter it is possible to obtain some idea about the final
result. The eye looks upon objects and determines the differences
either by the contrast in colors or contrast in dark and light. Nat-
urally the reproduction of dark and light on the photographic film
creates new difficulties, and it is sometimes better to over correct one
color to get the proper contrast.

A simple rule to follow when using the tri-color filters is to use
the filter which absorbs the color which is to be reproduced as black.
Thus if the green (B) filter is used for copying a map printed in
red lines or red typewriting, the result will be black lines or type-
written letters on the white paper. In case a red filter was used the
red typewriting would be entirely eliminated and only a white blank

214

Copying

sheet of paper reproduced. There will be colored objects which re-
quire certain compromises when using filters to show contrast or
gradation and detail as required.

The longer the focal length of the objective the more accurate
the filter must be for copying. This is why the 50mm lens is excel-
lent because of its short focal length.

Collapsible Reproduction Stand

While traveling or when working in libraries or similar places the
complete equipment must be kept as light and portable as possible. For
this use, the Collapsible Reproduction Stand is available. This apparatus
consists of a number of tubes fitting into one another, two supporting base
bars, and the extension arm for attaching the Leica or the Sliding Copy
Attachment. As the upright is about 22 inches high the No. 2 and No. 3
supplementary front lenses can be used. The vertical and horizontal tubes
have graduated scales in fractions of an inch.

When the Leica is used with the Front Lenses a plumb weight is used
for determining the exact center of the object to be copied. Then by refer-
ring to the lens table booklet, which is supplied with the lenses, the exact
focus and distance settings can be quickly made. A special light bracket
containing two lights is also available for attaching to the extension arm of
this outfit.

Fig. 137 Reproduction
Stand Equipped with Slid-
ing Arm, Illuminator,
Leica with Wintu Angle
View Finder, Measuring
Tape, and Wire Cable Re-
lease. - The Collapsible
Stand is Smaller but a
Similar Set-up can be
made.

215

Auxiliary Reproduction Devices

For certain types of close-up photography the Auxiliary Eeproduction
Attachments are of value. These attachments provide a fixed focusing ar-
rangement which can be applied for special areas from 1x1% inches up to
8% x 12% inches. The Belun Device is used with the Leica equipped with
the Elmar 50mm lens for obtaining 1:1 or natural size copies. This same
equipment is also available for the Hektor and Summar 50mm lenses, and
the Elmar 35mm lens. This equal-size reproduction device may be used for
copying portions of maps, coins, postage stamps, finger prints, handwriting
specimens, small insects, plants, seeds, and any other object which can be
included in the 1x1% inch area. The accompanying illustration will show
how this attachment is set up.

The Behoo Device is used for obtaining reduction ratios of 1:1%, 1:2
and 1:3 with the Leica. The greatest sizes of the objects at the three
different ratios are, 36 x 54mm, 48 x 72mm, and 72 x 108mm. As a com-
plete direction booklet is available for this attachment as well as the other
Auxiliary D Copy Devices it will not be necessary to make a reprint. The
Behoo Device uses three Extension Tubes for securing the three different
fixed focusing positions. When the No. 2 and No. 3 Front Lenses are used
there is an attachment known as the Beooy which covers areas from
3% x 5 inches up to 8% x 12% inches. Still another similar attachment is
known as the Bazoo which is a combination of the Behoo and the Beooy
Devices. The accompanying illustrations will give a good idea about the
way in which these copy attachments are set up.

Fig. 138 The Belun 1:1 Copy De-
vice used for Making Actual size
Copies 1x1% inches.

Fig. 139 Auxiliary Eeproduction
Device for use with Extension
Tubes and Front Lenses directly on
camera.

216

Copying

Special Rotating Copy Attachment

Still another type of copy attachment which has recently been made
available is the Rotating Copy Attachment which serves the same purpose
as the Sliding Focusing Copy Attachment already described. The Rotating
Device, as shown in the illustrations, can be used for copying- all areas
similar to the Sliding- Attachment. The booklet accompanying this Rotating
Copy Device gives complete tables and directions for operation.

Fig. 140 Rotating Stage Copy De-
vice. Note 5x Magnifier on Device
and 30x Magnifier at Lower Left.

Fig. 141 Rotating Stage Copy
Device as used in vertical po-
sition.

A very convenient attachment for the Rotating Copy Attach-
ment is known as the Rotating Stage Plate which can be used for
photographing small objects such as minerals, medical specimens, art
objects, photographs, or handwriting. This attachment (Fig. 140)
has a magnification range from 1:1 to 1:4 and focusing may be
secured by direct visual inspection of the ground glass or by using
the calibrated upright. It will be noted that there are three engraved
lines at the four different focusing positions on the upright. The top
line in each ease is for use with the Summar 50mm lens, the second
line for the Elmar 50mm lens, and the bottom line for the Hektor
50mm lens. At the 1:1 position the picture area is the same size as
the Leiea negative or approximately 1 x 1% inches while at the 1 -A
point the maximum area covered is 3 4/5 x 5 3/5 inches. "When using

217

the calibrate scale of the Kotating Stage Plate It is necessary to use
the intermediate rings recommended for this arrangement. Here
again it is possible to obtain from the Leitz Company a complete
direction booklet and also a special chart giving the exact areas cov-
ered with full information about intermediate tubes and the distances.

Fig. 142 Special Copy Device with
bellows extension. Note King Illu-
minating Device used for Securing
Proper Illumination of Specimens.

When using the Special Eotating Copy Attachment it is possible
to photograph objects 17 x 26 inches in size or minute objects only
1/10 x 3/20 inches in size. When a microscope is added as shown
in Figure 143 one can obtain magnifications up to several thousand
diameters. A brief summary of the basic equipment for the Special
Rotating Attachment as shown in Figures 142 and 143 is listed as
follows :

1. A 19 x 27 inch baseboard mounted on shock absorbing springs which
can be clamped rigidly or left in free suspension.

2. An upper and lower copying arm which can be moved as required for
focusing.

3. The upper aim is fitted with a clamping screw for holding the Eotating
Copy Attachment while the lower arm holds the lens mount and the
extension bellows.

4. A fine focusing ring is provided at the base of the lower arm.

5. The upright pillar is 4 feet high, and 1% inches thick.

6. A ring illuminator with rheostat provides the maximum of lighting
efficiency.

7. The 5X and SOX magnifiers are used with this equipment in the same
way as required for the Sliding Copy Attachment.

218

Copying

Fig. 143 Sliding Copy Device equipped for use with the Model FF 250-
exposure Leica. Illustration shows camera in position for use with the
microscope.

250 Exposure Leica Model FF

When many photographs are to be made of book pages or other sub-
jects the 250 exposure Leica is valuable as a time saver. This camera can
be used on the regular Sliding Arm, on a tilting top tripod, or in connection
with a special Sliding Copy Attachment. This camera can also be used
conveniently with the microscope for making many photographs in rapid
succession of still or moving objects.

Conclusion

As the subject of copying is such a broad one an entire book
could easily be written in order to include the many interesting
methods and applications. However this chapter will give the essen-
tials from which the Leica user can select the information required
for his own work.

219

The Fliers

A Four-Negative Photo-Montage

John T. Moss, Jr.

-220

FOR PROJECTION

WILLARD D. MORGAN CHAPTER 10

Undoubtedly the best way in which to view Leica pictures is
by projection upon a screen. In this way the projected image not
only has a large area, but it also yields more of a plastic quality
which closely resembles the original subject. Such pictures may
be projected in full natural colors, in various tones, as well as the
ordinary black and white film or glass slides. In these projected
pictures, a large group of people may be able to enjoy the same
picture at the same time. As most Leica pictures are made with
shorter focal length lenses, the negatives produce positives which
give an almost stereoscopic effect. This is due to the excellent depth
of focus in the Leica lens. In contrast to the projected positive, tlie
small 5 x 7 or 8 x 10 inch paper prints do not create the luminosity
and brilliance which are to be found in the projected picture.

One reason why a greater use and appreciation of the projected
image is not found is possibly because such pictures do not convey
the full interpretation of the original negative. This may be due to
the following :

1. The positive film or glass slide may lack contrast and brilliance.

2. The picture may not be composed properly on the slide or the
original negative may not have a pleasing composition.

3. The positive may be overexposed and thus be too dark on the
projected screen, or it may possibly be underprinted with the resulting* loss
of detail and depth.

4. The projected picture may have pin holes, dust spots, finger prints
or other blemishes.

5. The center of interest may be lost in a maze of useless detail.

6. Possibly the positive may lack sharpness due to improper focusing
or uneven pressure in the case of contact printing.

In many cases, an interesting Leica negative might be made into a
slide for projection instead of viewing the same picture on an 8 x 10 inch
enlargement. The projected picture presents a larger and more dramatic
effect. At the same time, the film or glass positive emulsion has a greater
latitude in the shadows and highlights of the image itself, as compared
to the paper enlargement. This is due to the fact that there is a light
illuminating the entire picture. In the projected image, even the blackest
shadows have illuminated details, providing the positives have been prop-

221

erly made, while in the paper print there cannot be such transmircecl

luminosity.

What Makes Good Positives

Leiea negatives can be prepared from many different subjects
wiiicli later may be made up into film and glass slide sets. For
example, these sets of positives may include pictures selected from
your vacation, travels, photographs of children and pets, or, you may
have sets illustrating your particular hobby by photographing: the
American scene, geological formations, architectural subjects, car-
toons, wild flowers, trees, insects and many other subjects which
lend themselves readily to photographic interpretation. After illus-
trating such subjects, it is possible to use these pictures for lecture
and visual education purposes, or for your own persona] entertain-
ment. In the case of film slides, these pictures may be printed in
groups of twenty to forty on one strip of film. On the other hand,
the 2 x 2 inch glass slides may be made individually and added to the
sets at any time. There is something to be said for each method.
The film slides are made more inexpensively while the glass slides are
more permanent and may be re-arranged during projection. In
addition to using the film and glass slides for general purposes, they
are valuable in the commercial field for use in demonstrating sales
methods, new products, as well as in training workers and salesmen.

The new Leica Duf ay color film is excellent for commercial,
educational, and for general subjects as well. This colorfilm pro-
duces a very satisfactory result when projected.

One of the most important advantages of making Leica pictures
for projection is that these pictures require small storage space.
For example, twenty-five rolls of positive film slides may easily be
carried in a small container. These film rolls may include over 1,000
pictures. With positive film costing only two or -three cents per foot,
the film of 1,000 pictures would entail a cost of about $3.00, while
1,000 8 x 10 inch enlargements will probably come to over $60.00. A
remarkable difference ! Even the 2x2 inch glass slides are quite
small and light in weight when compared to the standard 3*4 x 4
inch glass slides which are commonly used in the large projectors.

A thorough understanding of this chapter on the making of
Leica positives, along with the contents of the chapter on Visual
Education is essential The two are closely related. In the same
way, all the other chapters in this book are likewise allied, directly
or indirectly, to the making of film positives. The making of the
original Leica negative is just as important as the fine technique in

222

Making Positives

the making of the final film or glass slide positive for projection.
In other words, a poor Leica negative will not produce a superb
Leiea positive. On the other hand, an excellent Leiea negative can
very easily be made into a very poor positive unless proper steps
in its preparation are carefully observed.

The Two Positive Printing Processes

There are two ways in which to make the Leica positive film or
glass slide. The most common method is by actual contact printing
which is accomplished by placing the Leica negative directly in con-
tact with the unexposed positive film or glass plate. The other method
is by placing the negative into one of the Leica enlargers and then
printing directly by projection. Here again, there are advantages in
both methods, the former possibly being completed a little more rapidly
and at the same time requiring only a minimum amount of equipment,
while in the case of projection, it is easier to omit portions of the image
in case a negative must be balanced correctly in printing. The pro-
jection method helps in eliminating dust particles and also the best
portions of the negatives may be utilized. Both of these methods will
be described in detail later in the chapter.

Contact Positive Printers

The Eldia Film Printer represents one of the simplest arrangements
for the contact printing of Leica negatives either upon paper or positive
35mm film strips. This printer will hold approximately eight feet of posi-
tive film. The raw stock is wound upon one spool and unwound upon an-
other take-up spool after each contact print has been made. A ratchet
clicks for each space of three-quarters of an inch which represents the
single frame picture area. Two clicks of the ratchet represent the length
of the Leica picture. The Eldia Printer is supplied with the standard
frame size for the Leica negative. However, in case single frame nega-
tives are to be printed, it is possible to secure a single frame window
which is interchangeable on the Eldia Printer. The accompanying illustra-
tions will give a more definite idea about the appearance of the printer.

Fig. 146 Eldia Printer. For Making Contact Prints on Positive Film
or Paper

223

When using the Eldia Printer, it is possible to print each negative in
its original sequence, or if necessary, important negatives only may be
selected and printed upon the positive film stock, which is later developed
and used in one of the projectors. In doing this, the negative is pulled
past the window of the printer until the proper negative appears. The lid
is then clamped into position and the exposure made. Do not wind the
film when the top lid is closed or the film will become scratched.

_fU r

, 1 , „

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odoooooo"
i

-•• ° ° p — "• u

rooooo^iot

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Fig. 147 Positive Film or Paper Passes over Ratchet Wheel and under
Take-up Spool at Eight. Negative Film Passes Through Channel of
Hinged Cover.

Fig. 148 Alternate Method: Paper and Negative are Both Passed over
the Ratchet and over the Take-Up Spool at the Right.

Directions for Operating the Eldia Printer

Use standard safety base or non-inflammable positive film stock.
This may be purchased in various lengths from any photographic
dealer.

224

Making Positives

1. When preparing to load the Eldia Printer, cut off about five or
six feet of positive film and wind this upon the spool in the Eldia Printer
opposite to the winding spool which has a slightly longer knob for turning.

2. The winding or take-up spool is placed in the chamber next to the
small ratchet wheel which marks the successive advance of the Leica
frames during: printing. After the unexposed film has been wound upon
the supply spool, the free end is pointed and attached to the take-up spool.
Naturally, the film has been wound with the emulsion side out. The two
spools are ^ now placed in their respective chambers in the Eldia Printer,
as shown in the accompanying line drawing1.

3. Insert the Leica negative into the grooves which are to be found
on each side of the glass plate in the cover of this printer, the emulsion
side of the negative facing out. In other words, the emulsion side of the
unexposed positive and the emulsion side of the Leica negative must come
face to face in actual contact when the cover of the printer is closed.

4. After the printer has been closed, it is possible to judge the density
of the negative by holding the printer over a small light box, or in case
such a box is not available, hold the printer up in front of a low power

' light bulb for a few seconds in order to estimate the density of the negative
through the red plate which is to be found at the base of the printer.

5. One of the easiest methods of exposing each successive negative
when using this printer is by placing the apparatus under the Leica en-
larger. In case the light in the Leica enlarger is too strong, one or two
pieces of tissue paper may be placed in the position which would ordi-
narily be occupied by a negative for enlarging. This method provides bet-
ter diffusion of the light. The projection lens in the enlarger should be
thrown out of focus.

6. After one exposure has been made, unhook the cover of the Eldia
Printer and pull the Leica negative to the next picture. At the same time,
turn the positive film until two clicks are heard in the case of Leica films.

7. Make the exposure, after the density of the negative has been de-
termined by flashing on the small light under the printer. Proceed with
this method until all the pictures have been printed.

8. Make certain that the vertical and horizontal negatives are printed
in the same way. In other words, do not reverse the negatives so that the
vertical or horizontal pictures show on the screen in different directions
when projecting. Also, remember that if the first picture is to start at the
beginning of the positive film, the print should be made in such a way as
to show it at the beginning of the roll and not reversed, which may be the
case if care is not utilized. Simply remember that the positive picture
is placed into the projector upside-down with the emulsion side facing the
projection lamp.

9. Before printing the full roll of Leica positives, it is best to make
a few test exposures of various negatives with varying densities. To do
this, cut up short two inch lengths of positive film and place directly into
the printer so that the emulsion side will come into contact with the emul-
sion side of the negative when the cover of the printer is slipped shut.
Develop each test film in exactly the same way the full length of positive
film is to be developed. Three or four single exposure strips may be
easily developed in a small tray for the full time required for the devel-
oper. After the test films have been cleared in the hypo, rinse for half
a minute in water and then examine them by actual projection in the en-
larger or, better yet, use one of the Leica projectors. The wet emulsion

225

will very quickly melt if exposed too long to the heat of the projector.
Until you become an expert in judging the test exposures, it is always
best to examine these test films by projection.

10. Make certain that the glass plate in the Eldia Printer is thor-
oughly cleaned and also keep the negative and positive film free from
dust particles which may show on the finished positive film. Do not make
more than 36 pictures on one length of film, if it is to be developed in a
Reelo or Correx Tank.

11. After the completed strip of positive film has been exposed, de-
velopment is carried out in the Correx or Reelo Tanks in a manner similar
to that in which the Leica negative was developed. The only exception in
the process is that the film is developed in a special developer which ordi-
narily takes about five minutes for complete development.

12. The Glass Developing Drum can also be used for developing the
positive films. This drum is quite essential for developing the Leica
Dufaycolor film also.

All positive films made for projection purposes should be thoroughly
hardened after development. One of the simplest hardeners is Chrome
Alum described in the Developing Chapter. After the film has been hard-
ened, cleared in the acid fixing solution, washed, and then dried, it should
be rolled up with the emulsion side out if it is to be used in the Umino
or Umena projectors. If one of the Udimo projectors are to be used the
film may be wound with the emulsion side in.

Making the Leica Glass Positive

Glass 2x2 inch positives may be made in the Eldur Glass Slide
Printer very quickly by contact printing, as follows :

1. The method of inserting the Leica negative is shown in the ac-
companying illustration. The 2 x 2 inch glass plate is placed with the
emulsion side down directly over the Leica negative. The top hinged
pressure plate is then clamped down to hold the glass plate in contact dur-
ing exposure.

2. The Eldur Printer is then placed under the enlarger and the ex-
posure made by turning on the enlarger light for the correct exposure
time, which may vary from 2 to 10 seconds, depending on the negative and
the stop used in the enlarger lens. Always use the same illumination
when making positives in order to help in making the exposure estimate
more uniform. A test slide should be made first by turning on the en-
larger light and then make four exposures of 2, 4, 6, and 8 seconds each
on the same plate, by moving a card across at each step. When developed,
the test slide may be projected and the best exposure quickly determined
for the next slide. Sometimes it is more convenient and also less expen-
sive to use a Bromide paper which has the same speed as the plate for
testing.

3. The glass slides are developed in the usual slide developer which
is given in the same package in which the 2x2 inch glass slides come.

The Gevaert Company supplies the 2x2 inch glass slides in a medium
as well as contrast grade. Barnet slides may also be secured in the 2x2
inch size. When making glass slides, it is best to have both contrasts avail-
able, in order to obtain the best results from negatives which may be con-
trasty or flat. Usually, the contrast grade will be used. After exposing,
developing and fixing the glass slide, it should be tested in the projector

226

Making Positives

Fig. 149 Special Eldur Contact
Printer for Making 2x2 inch
(50mm x 50mm) Glass Slides

for correct exposure and development. While still wet, it may safely be
projected two or three seconds. After making- thousands of glass slides,
I still recommend that each slide be placed in the projector and flashed
upon the screen for an instant since this is the only way in which the finest
glass slides can be produced. If the light of the projector is flashed for
only two or three seconds through the wet slide, there will be no effect
upon the positive. However, if the wet plate is allowed to remain in the
projector for a half minute or more, the emulsion will warm up and melt,
thus ruining the slide. It is very easy to have the projector^ in the dark-
room for this purpose. A small image projected upon a white cardboard
is sufficient for determining the quality of the slide.

A good developer for use with the 2x2 inch glass slides is prepared
as follows:

Gevaert Contrast Developer for Slides

Metol 11 grains 0.75 grams

Hydroquinone 45 " 3.0 "

Sod. Sulphite (des.) 175 " 25.0 "

Sod. Carbonate (monohydrate) 350 " 53.0 "

Pot. Bromide 8 " 0.5 "

Water to make 16 oz. 500.0 cc

The chemicals must be dissolved in the order named. A very good
plan is to dissolve every product in water, mixing in the order named. The
bath is then filled up with water to the mentioned quantity.

At a temperature of 65° P., lantern plates develop in from 1% to
2% minutes.

Make certain that the exposure is such that the positive plate will
remain in the developer for at least two and a half to three minutes
without becoming overdeveloped. In case the image flashes up too
soon and the plate is removed at the same time from the developer, the
resulting positive will not have the rich transparency and brilliance
which occurs when the plate is properly exposed and fully developed.
This is where many workers make a mistake. Never underdevelop

227

a positive but on the contrary, carry the development to the recom-
mended length of time. Even a minute over this time will be better
than a minute under, The Universal Developer described in the chap-
ter on Enlarging Papers may also be used for positive films or glass
slides.

"Whenever more contrasting results are required on positive glass
plates, it is necessary to use a contrast developer. The Eastman D-ll
Developer produces good contrast, while the Eastman D-9 Caustic
Developer produces extreme contrast. The D-9 Developer is par-
ticularly well suited for line work, where extreme contrast is desired.

Hydroquinone- Caustic D-9 Developer

For Process and Panchromatic Process Films and Glass Slides
For Tray Development

Stock Solution A

Avoirdupois Metric

Water (about 120° F.) (52° C.) 16 ounces 500.0 ec.

Sodium Bisulphite % ounce 22.5 grams

Hydroquinone % ounce 22.5 grams

Potassium Bromide % ounce 22.5 grams

Cold water to make 32 ounces 1.0 liter

Sirock Solution B

Cold water 32 ounces 1.0 liter

Sodium Hydroxide (Caustic Soda) 1% ounces 52.5 grams

Dissolve chemicals in order given.

Use equal parts of A and B and develop for not more than two min-
utes at 65° F. (18° C.).

Cold water should always be used when dissolving sodium hydroxide
(caustic soda) as considerable heat is evolved. If hot water is used, the
solution will spatter with violence and may cause serious burns if the
alkali spatters on the hands or face. Solution A should be stirred thor-
oughly when the caustic alkali is added; otherwise the heavy caustic solu-
tion will sink to the bottom.

Wash thoroughly after development and before fixing to prevent
stains and dichroic fog.

When using the D-9 Caustic Developer, mix a small amount in a
small tray or dish which is only a little larger than the 2x2 inch glass
plate. Use developer only sufficient to cover the plate. Upon mixing the
two solutions, the developer oxidizes quite rapidly and after eight or ten
minutes, at the most, the developer should be discarded. In the meantime,
the slides may be developed. As this is a strong and rapidly working
developer, make certain that the positive plates are not overexposed,
since fine details in a line drawing or a printed page will not show dis-
tinctly unless correct exposure has been made. However, with the correct
exposure and the caustic developer, a brilliant contrast negative will result.

Using Projection Paper for Testing

When making film or glass slides, it is possible to use a bromide
projection paper cut into small sizes and used in place of the film or

228

Making Positives

Fig. 150 Saloon of the Gold-Rush Days Willard D. Morgan
PRESERVING THE EARLY AMERICAN SCENE

Fig. 151 Country Club of Gold-Rushers

Willard D. Morgan
229

glass plate for testing the exposures, A paper, such as the Agfa
Brovira medium, or contrast has a printing time very similar to posi-
tive film or glass plate emulsions. With a little experience, the proper
ratio between the paper and the positive emulsions may be easily de-
termined for this paper, as well as any other make of Bromide papers.
Such a method of making tests is economical because a full glass plate
does not have to be exposed in order to find out the correct exposure
time. At the same time these contact paper prints may be used for
indexing purposes or for cross references after the slides have been
made. It is a good plan, in fact, to make a paper contact print of
every negative which is made into a positive for projection. These
paper prints are useful for classifying the pictures later. There is
a special metal pressure plate which may be placed over the square
rubber plate which is used in the Eldur Printer. This metal pressure
plate permits the making of paper contact prints in the Eldur Printer.
It is quickly removed when glass plates are to be made.

After each positive glass plate has been developed, it should be
rinsed for a few seconds in fresh water and then placed in the hypo
clearing solution for about eight to ten minutes. After clearing, the
slide is then placed in running water and washed for one-half hour.
When washing has been completed, wet a piece of cotton or nse a wet
viscose sponge for swabbing off both sides of the plate which is then
placed in a drying rack in a location free from dust. A close-meshed
linen cloth may be laid over the drying rack in order to keep out dust
particles which may settle on the wet emulsion of the plate and later
show up on the projection screen.

When all the slides are dry, they should be projected before bind-
ing in order to cheek on the quality. In case there are scratches, pin
holes or other defects, the slide must either be touched up or discarded.
Small pin holes and breaks in the emulsion can usually be eliminated
by spotting with a fine brush and black spotting ink. The Chinese
Ink stick, which may be purchased at most photographic dealers, is
very handy for this purpose. Some slides may require opaquing
around the principal object. This is easily done by painting with a
good opaque solution which dries quickly. Slides showing machinery
parts, and copies of irregular subjects which are to be shown without
a background, will require this method of opaquing before binding.

Mounting the Finished Glass Slide

After the glass slide is dry, secure a clear cover plate together with
a cut out mask and a package of lantern slide binding tape. The binding
tape can be cut into four lengths of two inches each, or if preferred, one
full length about eight and one-half inches long may be cut. Place the

230

Making Positives

cut out paper mask over the emulsion side of the positive in such a way
that the clear portions of the positive surrounding the picture are covered.
Next, place the clear cover glass, which has previously been washed and
polished dry, over the mat and the positive plate. Hold both plates to-
gether and paste the paper binding tape around the edges. Make sure
that the emulsion side of the positive plate is always covered by the glass
plate. If the emulsion side is on the outside, it will quickly be damaged.

Film positives may be cut with scissors and bound between glass
plates if desired. Some Leica users prefer this method since the pictures
may be made at smaller expense. Two or three positives may be made
of the same negative in case there is any doubt about the exposure. The
best positive is then selected for binding between the two clear glass
plates with the paper mask between. The film positive should be attached
to the paper mask by one or two small pieces of the paper binding: tape
in order to keep the picture centered while "binding. This method is espe-
cially recommended for the natural color films, such as the Agfacolor,
Dufaycolor and Lumiere.

After the glass slide is bound, it should be spotted by placing a
small white square of gummed paper or photo cloth in the upper right
corner of the slide when it is in its correct position for projecting. In
other words, hold the slide before you so that it looks correct. That is,
the slide should appear in the same orientation as the original subject.
Then, turn the slide so that the subject is up-side-down with the emulsion
side facing toward you. Place white spot on the tipper right corner of the
slide. When the slides are being projected, it is very easy to place them
in the projector in their proper position without difficulty, simply by watch-
ing the reference spot.

Ail glass slides spoiled by wrong exposure, developing, or any other
cause, should be saved and used for cover glasses later. These discarded
slides may be soaked in hot water and strong soap in order to soften and
remove the emulsion. A razor blade is good for scraping off the emulsion.
Give the glasses a final wash in another soap and water bath and then
wipe thoroughly dry with a clean linen cloth. The glasses are now ready
for use in binding the good lantern slides.

Still another method of preparing film positives for projection is
by mounting three positive films between two clear glass plates which
measure 35 x 120mm. These plates are matted and bound, similar to the
2x2 inch glass plates. The Udimo Projectors have a special slide holder
for accommodating this longer sized plate. In the case of stereo positives,
this method of binding is excellent as the Stereo Viewer accommodates
the 35 x 120mm slide.

Making Film or Glass Slides by Projection

My favorite method of making film or glass slides is by using one
of the Leica enlargers. The negative is placed in the enlarger with the
emulsion side facing down as usual, while the unexposed film or glass
plate is placed on the baseboard after exact focus has been obtained
on another focusing plate. When unexposed positive film is used in
the Eldia Printer, the top plate of the printer is clamped shut as usual.
However, the picture is projected through the glass plate upon the
positive film. Before making the exposure, focus the negative upon

231

a white area the exact size of the Leica negative and also in the exact
plane of the film in the printer. A block of wood may be cut for this
purpose or two printers may be used.

Film positives may also be made by using the Leica camera loaded
with positive film without a lens. The picture is focused from the
enlarger directly into the camera after the focal plane shutter has been
set at time exposure. Once the correct focus and position have been
determined, the entire strip of film may be exposed. A thin block of
wood 3%mm thick (the exact thickness between the back of the Leica
and the face of the pressure plate) may be used for focusing the image
before the camera is placed into position. The face of the wood should
be painted white and the exact frame size of the picture ruled off in
black crayon for a guide when focusing.

A single frame IS x 24mm film positive may be made by reduc-
tion from the Leica size 24 x 36mm negative. The Eldia Printer
equipped with a single masking window may be used for this purpose.
The Leica Enlarger is equipped with a 6cm extension tube between
the 50mm lens and the focusing mount. In this way, it is easy to
reduce the Leica negative to single frame size. All Leica projectors
are equipped for single frame as well as double frame projection. As
there are many projectors available for single frame pictures only,
this method of making positives will naturally be of great value for
such projectors.

"When using the 2x2 inch glass plates, it is simpler to place one
of the undeveloped plates on the paper easel of the enlarger. The
plate may be pushed into the corner of the easel in such a way that a
second plate may be replaced after the image has been centered on the
focusing plate which contains a penciled outline 1 x iy2 inches in size,
representing the size of the Leica negative. If preferred, the picture
area may be made 3 x 4cm in size and later the picture masked off
by using the short strips of lantern slide binding tape. This 3 x 4cm
size can be projected only in the Udimo projectors.

An orange filter is convenient to use while making glass slides.
Such a filter may be thrown across the projected negative image in
order to make certain that the unexposed glass plate is properly cen-
tered before the exposure is made.

The important part of the Leica negative is easily centered upon
the glass plate. All the unessential parts of the negative are eliminated
because the projected picture may be made larger or smaller in order
to eliminate certain parts of the negative. At the same time, it is not
difficult to shade part of the picture during exposure in order to bring

232

Making Positives

out certain parts of the positive, sudi as, a dense sky, or possibly some
other portion of the negative may have a strong highlight which should
be printed longer. In fact the projection method of making glass slide
positives is the Ideal way in order to insure the best results.

In some cases, it is necessary to make 3^/4 x 4 Inch standard lantern
slides for use in the larger projectors. Such slides are made by using
the Lelca enlarger and following similar methods which apply to the
smaller 2x2 inch glass slides. If the original Lelca negative is de-
veloped properly, It is possible to make 314 x 4 inch glass slides which
will produce beauty and brilliance equal to slides made from larger
negatives when projected.

When using the Valoy or Focomat enlargers for making film or
glass positives, it is necessary to use either a 3cm or 6cm extension
tube between the 50mm lens and the focusing mount of the enlarger.
When the 3cm tube is used, keep the lens barrel pulled out and locked
in position. However, in case the 6cm tube is used the lens barrel may
be pushed in as far as it will go. The correct focus is obtained by
turning the focusing mount of the enlarger. Naturally, other extension
tubes or any combination of tubes may be used depending upon the
results required. In case a longer working distance is required be-
tween the lens and the positive, a 6cm tiibe and the 90mm Elmar lens
may be used very successfully.

Fig. 152 Laver Combination Print-
er. A complete Unit Easily Con-
vertible for Contact Printing on
Paper, Paper Strips, Film or Glass
Slides

Operating the Combination Professional Printer

When a more universal positive printing- outfit is required, the Laver
Combination Printer is recommended. The Important features of this
printer are listed as follows:
1. Single frame and double frame film slides may be made.

233

2. Single frame, Leica size double frame, 3 x 4cm and 4 x 4cm glass plate
positives may be made by using a supplementary plate printing attach-
ment.

3. All metal construction, with enclosed lamp housing, containing a 15-
watt bulb for making the exposures.

4. Rheostat control for varying light intensity.

5. A small red light burns continually in the lamp housing in order to
show the proper exposure, or density of each negative.

6. Contact button for turning on the white light for making the exposure.

7. Slots on each side of the printer permit the insertion of a thin piece
of cardboard for use in shading parts of negatives during the ex-
posure.

8. Film housing will hold up to 35 feet of positive film. The exposed film
may be cut off and developed as used.

9. On each side of the glass plate, under the negative, there is a small
line drawing, showing which way the negatives should be printed in
order to appear in the finished positive film roll in the proper upright
or horizontal positions.

10. When the positive film chamber is moved out of position, a metal plate
automatically covers the exposed portion of the positive film. Naturally
the printing should be done under a red safety light in the darkroom.

The positive film is loaded into the Laver Printer by removing the
top portion of the film housing and rolling the film directly upon the
spool opposite to the ratchet spool, similar to the one in the Bldia
Printer. Make certain that the film is wound with the emulsion side
out when loading and attach the free end to the take-up spool which
is wound in such a way that the film emulsion will be on the inside.
In other words, the film passes over the ratchet wheel and down under
the take-up spool. As the film is advanced, a distinct click will be
heard for each single frame space. Two of these clicks represent the
length of a Leica negative. After the film has been inserted, place
the upper part of the housing back into position.

The making of film and glass slides by contact printing is carried
out by methods similar to those previously explained.

In using either the film slide attachment or the glass slide attach-
ment on the Laver Printer, it is possible to see picture numbers or
special marks which may be made on the film margins for reference
when selecting the proper negative for making the positive printing.

Using the Belun Attachment

Still another method of making positives is by using the Belun 1 :1
copy attachment. For this set-up secure a light box for illuminating
the negative which is to be copied directly upon the positive film which
has been loaded into the Leica camera. A 15-watt bulb will be sufficient
for illumination. Set the Belun copy attachment over each negative
to be copied and make the exposures. A few test exposures should be

234

Making Positives

made before running through the entire film. A short length of posi-
tive film may be loaded into the camera for making- the test shots.
By using the Belun attachment sections of larger negatives can be
copied and made into positive film slides for projection also. Then
by using the Sliding Focusing Copy Attachment any sized negative can
be copied for positive film slides.

Fig. 153 My Friend Lionel

Henry M. Lester

235

Fig. 155 Sky Kockets

Elmar 50mm lens, wide open, 1 minute exposure

236

E. Scott Pattison

WILLARD D. MORGAN CHAPTER II

After the positive film or glass slide lias been made, the next step
is to show the finished pictures on a projection screen. In doing this,
it is necessary to select one of the projectors described later in this
chapter.

By projecting Leica pictures, you have an opportunity to show
one picture to a group of friends wTho may be assembled for the occa-
sion. In this way, all can be united in viewing one picture at a time
and also in talking about each picture as it is shown. Thus, a very
profitable half hour or an entire evening may be spent. Each pic-
ture is thus presented in its fullest advantages of large size and with
its three dimensional effects which come nearest to interpreting the
original scene.

In the field of visual education and industrial selling, the use of
positive pictures for projection is of immense value. In the industrial
sales field, for example, it is possible to use the Lelca Camera to
photograph actual manufacturing processes and later arrange these
pictures in slide form for projection. For example, there is a largo
industrial firm which uses the Leica Camera very successfully by
collecting the latest developments and uses for their product from
different state managers. These pictures are then assembled and
printed along with appropriate titles on film strips. The duplicate
strips are later mailed out to the various branches for the regular sales
meeting of the district salesmen. Thus each district is kept in con-
stant touch with all the developments throughout the country.

The Various Projectors Available

There are five different Leica projectors available for showing
Leica positives. These projectors range from the small Umino pro-
jector to the large 400-watt Udimo projector. In selecting the proper
equipment for your purpose, it is important to consider the various
specifications of each projector. Two of the most generally used
projectors are, the small miniature Umena Projector, and the Udimo
100 Projector. The Udimo 250 and Udimo 400 projectors are of

237

special value for use in projecting natural color pictures and also for
use in larger rooms where a longer projection distance is required.

Fig. 156 Udimo - 100 Projector,
Shown Complete with Camera Lens,
Film Magazines and Transport
Gate

The Udimo 100 Projector

The Udimo 100 Projector is considered to be the standard model
projector which is used by many Leica owners. The specifications
and directions for using this projector are given as follows :

1. Height, 9*/2 inches, width of base, 5 inches, length of base, IVs inches.

2. Bayonet socket for holding 100-watt prefocused projection bulb.

3. Detachable heat absorption screen. When glass slides are being pro-
jected, this heat filter may be removed, thus slightly increasing the
brightness of the screen picture.

4. The condenser of this projector is made up of three elements, the front
element being interchangeable for use with lenses of various focal
lengths. This system insures the full illumination of every picture
projected with the various lenses providing the proper front condenser
is in position. Complete information about the interchangeable con-
densers is given later.

5. The top cover plate of the projector housing may be removed when the
tubular projection lamp is to be changed. When removing the lamp,
simply pull directly out of the socket. When placing a new lamp in
position, make certain that the filaments are parallel with the condenser
system.

6. The entire lamp mounting may be removed by turning the projector
up-side-down and removing the three large screws which hold the bot-
tom plate in position. In case the central lamp housing is out of align-
ment, proper centering may be done by adjusting the set screws on
the base plate.

7. The intensity of the projected positive is increased by means of a
mirror reflector mounted at the rear of the projection lamp.

8. The film slide attachment which is mounted on the front part of the
projector may be rotated in order to show horizontal and vertical pic-
tures in their proper orientation. There is a small spring catch
mounted just above the revolving attachment. This catch may be re-

238

Projecting

leased when the attachment is changed to a vertical or horizontal
position.

9. The various slide masks may be used for showing film or glass slide
positives in various sizes, from single frame up to 4 x 4cm. All these
masks and slides are quickly interchangeable in the film or glass slide
attachment which is mounted in front of the projector and secured into
position with four knurled knobs.

10. AH the Leica lenses with the exception of the 35mm wide angle may
be used with this projector as well as the Udinio-250 and Udimo-400
Projectors. There are also two special 80mm and 120nim projection
lenses available for these projectors. A special base tube or receiving
socket is used with the 80mm and 120mm projection lenses for attach-
ing to the projector. All the Leica lenses are screwed into the film or
glass slide attachment directly without the use of any intermediate
tubes.

11. When loading the positive film slide into the Udimo film slide attach-
ment, proceed as follows:

a. While facing the projector from the front, remove the left film
drum and draw out the film transporting gate. Make certain
that this gate is thoroughly cleaned. The front plate may be
removed by lifting out from under the two springs which hold
it into place. At the same time, the lower glass plate may be
slid to one side and removed by slightly raising the spring band
which will be seen along the top side of the film gate. This
plate may be replaced by a plate with single frame window In
case single frame film slides are to be used. Otherwise, clean
the original plate and place it back in position along with the
film transport gate.

b. When replacing the film transport gate, push it into its slide-
way as far as it will go. While facing projector, this gate Is
pushed into position from the left side, the same side through
which the positive film strips are started.

c. Replace the left film housing and insert the positive film roll
into this housing with the beginning of the roll projecting
through the guide which opens directly into the film sliding
gate and is transported through this gate by turning- the ratchet
wheel.

d. The turning knob of this ratchet wheel must be pressed down
each time the film is transported, otherwise, the film will not
turn. After the film has been transported, raise the turning
knob. In doing this, the glass pressure plate automatically
presses against the film and holds it in a perfect plane during
the projecting. When the turning knob is depressed, this glass
plate automatically separates at the same time the film is being
transported. This precaution prevents any possible scratching
of the film.

e. As the film is turned through the transport gate, it auto-
matically enters the opposite film chamber on the right and
winds into this chamber.

f . Start the positive film through the transporting device with the
emulsion side facing the projection bulb being sure that the
horizontal images of the film are inverted or upside down.

239

12. There are four interchangeable condensers for use with the three Udimo
Projectors. These condensers are supplied for use with the various
lenses of different focal lengths. Each condenser has marks on the
side, indicating the focal length of lenses required for the particular
condenser. The exact specifications of each condenser are given as
follows :

a. Interchangeable Condenser marked "5" for use with Summar,
Hektor and Elmar 50mni lenses, for use with Udinio 100 and
Udimo 300 Projectors.

b. Interchangeable Condenser marked "5VIIK" for use with Sum-
mar, Hektor and Elmar 50mm lenses for Udimo 400 Projector
only.

c. Interchangeable Condenser marked "7.3-8-9" for use with Leica
lenses Hektor 73mm, Elmar 90mm, and special projection lens
Milar 80mm focus.

d. Interchangeable Condenser marked "10.5-12-13.5" for use with
Leica lenses Elmar 105mm, Elmar 135mm and special projec-
tion lens Dimax 120mm focus.

13. The special 120mm projection lens is known as the Dimax, while the
80mm special projection lens is known as the Milar.

14. The Glass Slide Changer as illustrated is excellent for use when show-
ing" the 2x2 inch glass slides in the Udimo Projectors. This Slide
Changer may be used in the special glass slide holder, or it may be
used in the Film Slide Attachment after the two film drums have been
removed.

Fig. 157 Udimo-250 Projector. Illus-
tration Shows Lamp Housing Only.
All attachments are Interchangeable
with the Various Udimo Projectors

Fig. 158 Udimo-400 Projector.
Illustration Shows Lamp Housing
Only

240

Projecting

Pig. 159 Glass Slide At-
tachment, Interchangeable
for all Udimo Projectors

Fig. 160 Glass Slide
Holder, Interchangeable
for all Udimo Projectors

All the film and glass slide attachments are interchangeable for
use on the Udimo 100, Udimo 250 and Udimo 400 projectors. The
main differences in these projectors are in the lamp housings. 100,
250 and 400-watt projection bulbs are used respectively in each Udimo
Projector. The height of the Udimo 250 Projector is 11% inches,
while the width of the base is 6 inches and the length 9 inches. The
Udimo 250 has a special self-contained heat filter in the condenser
system. The height of the Udimo 400 Projector is 12% inches, while
the width of the base is 7% inches and the length 13% inches. The
Udimo 400 Projector is equipped with a special water cooling jacket
which should be filled with distilled water before using.

Fig. 161 Base Tube for At-
taching1 Special 80mm and
120mm Projection Lenses, In-
terchangeable for all Udimo
Projectors

Fig. 162 Film Transport Gate,
Interchangeable for all Udimo
Projectors

241

A special Elevator Plate may be attached to any of the Udimo
Projectors. There are two small threaded holes in the base at the
front of each projector for attaching the Elevator Plate. This Eleva-
tor Plate may be attached to the base of either projector and set at
the proper position so that the projected picture is perfectly centered
on the projection screen. The film and glass slide attachments are
all interchangeable for the various projectors.

Table showing screen areas for various projection lenses.
Screen Distance and Screen Areas in Feet

Lens 6ft. 9ft. 12ft. 15ft. 18ft. 21ft. 24ft.

Elmar f:3.5 50m

Hektor f :2.5 50m 3.9X2.7 6X3.9 8.1X5.4

Summar f:2 50mm

Hektor f :1.9 73m 4.5X3 5.7X3.9 7.2X4.8 6X9

Eimarf:490mm 3.6X2.4 4.5X3 5.7X3.9 6.6X4.5 8.1X5.4

Elmar f:6.3 105mm.... 3.9X2.7 5.1X3.3 6.3X4.2 7.2X4.8 8.1X5.4

Elmar f:4.5 135mm..,. 3X2 3.6X2.44.5X3 5.4X3.6 6.3X4.2

Milar 80mm 3.9X2.7 5.4X3.6 6.3X4.2 8.1X5.4 6.3X9.5 7.2X10.8

Dimax 120mm 3,6X2.4 4.2X3.7 5.4X3.6 6.3X4.2 7.2X4.8

Pig. 163 Udimo-750 Projector complete with 250mm pro-
jection lens and special film transporting device
which accommodates film lengths up to 70 feet

The Udimo-750 Projector

The Udimo-750 Projector is really a universal projector which
can be used for screen distances between 10 and 100 feet or more.
All the Leica lenses with the exception of the 28mm and the 35mm
can be used with this 750-watt projector. In addition, there are the
80, 120, 150, 200, and 250mm projection lenses to select from. The
high light intensity makes it possible to project color pictures upon
a large screen and still retain the brilliance required.

242

Projecting

There are six different interchangeable condensers available for

all the various projection lenses. The three additional condensers
not listed on page 240 are added as follows :

e. Interchangeable Condenser marked "15" for use with the 150mm
Dimax projection lens.

f. Interchangeable Condenser marked "2CFy for use with the 200mm
Dimax projection lens.

g. Interchangeable Condenser marked "25" for use with the 250mm
Dimax projection lens.

As a supplement to the table on page 242 the following projection
distances and screen areas will give additional information of value:

Lens 35 ft. 60 ft. 80 ft, 100 ft.

Dimax 150mm 6X9 10 X 14%

Dimax 200mm 7% X 11 % 10 X 14%

Dimax 250mm 6X9 8X12 10X14%

All measurements are given in feet

The Udimo-750 has a special heat filter and water jacket cooling-
chamber to prevent the overheating of positive films during projec-
tion. All the interchangeable accessories used with the other Udimo
projectors may also be used with the Udimo-750. A special film
attachment may be used which accommodates all film lengths up to
75 feet.

Fig. 164 The Umino (50 watt) or Umena (100 watt) Miniature Projector
for Single and Double Frame Film Slides or Glass Lantern Slides

The Umino and Umena Miniature Projector

One of the simplest and most compact projectors available for
showing Leica film or glass positives is known as the Umino Projector
which contains a 50- Watt projection bulb. This projector is so small
that it can easily be carried in a brief case along with a supply of
positive film or slides. As this projector has so many distinct ad-

243

vantages, it Is recommended for use by all Leica users who are inter-
ested in projecting their pictures. When the Umino projector is
equipped with a 100-Watt projection bulb it is referred to as the
Umena Projector. The specifications and directions for using this

projector are given as follows :

1. Height 5 1/2 inches, length 7 inches, width 2 1/2 inches, weight
2 1/3 Ibs.

2. 80mm projection lens in focusing mount, 50 or 100-watt projection

bulb available.

3. Six-volt bulb may be used with ordinary automobile storage bat-
tery when the usual electric current is not available.

4. Front film housing may be rotated for showing vertical or hori-
zontal pictures after loosening the set screw No. 1. The complete
front rotating portion of the projector may be removed after
loosening the set screw No. 8. After this set screw is loosened,
simply raise the front attachment and remove from its position.

5. When a 100-watt bulb is used, a heat absorption filter is inserted
into position as indicated by No. 5. A spiral spring No. 4 is re-
moved or replaced for holding the heat filter in its proper position.

6. In case the condensers No. 6 and No. 7 are to be removed for
cleaning, it it only necessary to remove the spiral springs which
hold them in place.

7. When loading the strip of positive film into the Umino Projector,
unhook the clamp No. 11 and swing out the pressure plate No.
12. The film roll may be inserted into the film chamber No. 34,
while the free end of the film roll is passed down under the metal
guide of the lower chamber. After making certain that the per-
forations of the film mesh with the cogs on the turning rachet
wheel, close the hinged pressure gate No. 12.

8. After the film has been placed in its proper position, turn the film
transporting knob No. 20 slowly until the first frame of the film
strip comes into exact position on the projection screen. This
frames the first picture and from then on the knob is pulled out
and turned for each picture. A slight click is heard as the knob
is turned. Each click represents a space of a single frame positive,
thus two clicks are necessary to place each Leica size positive in
position.

9. When 2x2 inch glass slides are to be used, the front film pressure
plate No. 12 is removed. In doing this, simply unscrew the knob

244

Projecting

No. 17 part way until the cross plate No, IS separates from the

glass pressure plate No, 12. Then, remove the glass plate entirely.
Next, draw out the back glass pressure plate X5. 0. In this way
space is left for Inserting the 2x2 inch glass slides which may be
pushed through as required. "When using the glass plates it is
not necessary to revolve the front housing because the glass plates
have the pictures already mounted in either horizontal or vertical
positions.

10. When changing the projection bulb, loosen the set screw No. 10
and then raise and remove the lamp housing No. 9. The interior
metal lamp housing is pushed back, thus leaving the projection
bulb free for changing.

Fig. 165 Cross section of
Umino or Umena Minia-
ture Projector, Showing
Detail of Optical System

Fig, 166 Cross sec-
tion of Umino or
Umena Miniature Pro-
jector, Assembled,
Ready for Projection

When using the Umino Projector, make certain that the film
positives have been hardened in order to prevent scratching during
projection. If the positives have been properly processed, danger of
scratching the film slides during projection will be practically elim-
inated.

245

Titles for Film

Whenever possible, try to include printed titles in your film
strips. A few titles scattered through a film strip will give added in-
terest as well as information to the people who are viewing pictures.
The strip can start with a special title and short description about
what the pictures will cover. Titles are easily made by using one
of the copy attachments referred to in the chapter on Copying with
the Leica Camera. Boards containing movable letters are available
for setting up titles.

If a title board cannot be secured, simply use a black slate and
letter the wording with chalk. Make the photograph and then erase
the lettering for the next sub title. In fact, titles might even be let-
tered across actual Leica enlargements which may present an interest-
ing background. With a lettering board many interesting titles may
be worked up for use with your film slides.

Advertisement
246

Rudolf Hoffmajin

Projecting

Storing Positive Pictures

All film slides and glass slides should be kept in containers free
from dust. Such containers may be secured from the regular photog-
raphic dealers, or, if preferred, special containers can be made to cover
any individual requirements. The small metal cans with covers on
which the titles of the film slides may be written are excellent. These
tins may be purchased on the market. Another way to keep film slides
is by using the regular film storage boxes which contain cross-sections
with spaces for about 25 rolls of film. The glass slides are easily kept
in small boxes with hinged lids.

As your film and glass slide library grows, it will be necessary for
you to develop a special indexing system so that any picture may be
located instantly when desired. In the case of film slides, it is con-
venient to make paper contact prints of every picture on a single
strip of film. These contact pictures are then mounted onto an index
card which contains titles, numbers and complete information about
that particular film roll. Contact prints of the individual glass slides
may also be made and mounted on individual indexing cards, along
with the proper title and descriptions. In the case of the glass slides,
it is very easy to group the subjects under various classifications, such
as, buildings, street scenes, birds, boats, portraits, flowers, or any other
subject. As the glass and slide collection grows, a valuable index and
cross reference system may be built up. The slides are then available
for instant use for showing in the home or in preparing special lec-
tures or demonstrations.

UMINO AND UMENA PROJECTION TABLE

Distance in feet
between Umino or

Umena and Screen Image Screen Image

projection screen Leica size single frame size

6 2 ft. 5 in. x 1 ft. 7 in. 1 ft. 7 in. x 1 ft 3 in.

9 3 ft. 7 in. x 2 ft. 3 in. 2 ft. 3 in. x 1 ft. 8 in.

12 4 ft. 10 in. x 3 ft. 2 in. 3 ft. 2 in. x 2 ft. 5 in.

15 6 ft. x 3 ft. 10 in. 3 ft. 10 in. x 3 ft.

18 7 ft, 2 in. x 4 ft. 8 in. 4 ft. 8 in. x 3 ft. 6 in.

21 8 ft. 4 in. x 5 ft. 6 in. 5 ft. 6 in. x 4 ft. 2 in.

24 9 ft. G in. x 6 ft. 3 in. 6 ft. 3 in. x 4 ft. 8 in.

247

Fig. 168 Dachshunds
(Not a Stereo!)

Ivan Dmitri

248

HENRY M. LESTEB CHAPTER 12

Our keen appreciation of realism in photography finds its fullest
expression in our fondness for color pictures and stereoscopic views.
The latter, known among graphic arts as three dimensional photogra-
phy, is, for the time being the only method of rendering pictures so that
the subject looks round and plastic. It is unfortunate that at present
we are unable to lend this plasticity to single picture views obtained
by ordinary, two dimensional photography, which always has, and
still is endeavoring to assist our imagination to see things in pictures
as we are accustomed to see them in life. By means of lighting,
suitable backgrounds and skillful placement of the object within its
environment, photographers are trying more or less successfully to
give their pictures the effect of roundness and depth. But so far,
photography has not been able to find a substitute for that lifelike
rendering of depth in anything but the double image secured by view-
ing the subject from two points.

There is nothing new about a stereo camera. But the manner in
which stereo views are obtained with a Leica camera is a decided
departure from the old-fashioned methods of stereo photography.
Before the Leica made its entrance into this field, a stereo camera had
to have two lenses. In better cameras of this type these lenses had
to be of the matched type, synchronized as to lens aperture and shut-
ter action. The stereo feature introduced by the Leica consists of
taking stereo pictures with one lens only.

The problem was solved with remarkable simplicity. Two prisms,
placed about 70mm apart along a horizontal axis are made to act as
small periscopes, bringing the two respective images together in front
of the regular Leica lens. Each of these two images enters the camera
and reaches the film plane through its respective half of the lens.
Thus two separate images are formed upon the film, each measuring
half of the Leica frame; lSx24mm. There is no dividing line be-
tween these two images : they merely join each other, forming a nar-
row fade into one another, thus using the maximum space available.

A negative thus formed is made into a positive transparency by
contact printing upon 35mm positive film without any of the customary

249

reversal of images. The positive is then viewed through a slightly
modified form of the same periscopic double prism, where the process
is reversed. Here the images are picked up from the double frame
separately, and carried to two eyepieces, thus giving full stereo effect.

The Leica method of stereo photography has also the advantage of
seeing stereo pictures at their very best because of the added
luminosity, plasticity and brilliance of viewing positive transparencies
instead of paper prints. All this gives the picture an added sense of
realism. Of course, if paper prints are preferred, they may be made
just as easily by enlargement to the size desired.
The Stereo Equipment

The Stereoly attachment consists of two units: the photographing unit,
which is placed over the standard 50mm lens, and held in place by means of
a small arm fitting into the camera clip; and the viewing- unit, which has
adjustable eyepieces and a slotted channel for the film. The viewing unit
can be held in hand or attached to a convenient stand. The Stereoly taking
unit has its own view finder, which replaces that of the camera. Since
each of the two pictures obtained is only half as large as the regular
Leica frame, only half the area covered by the 50mm lens is available.
The Leica , must always be held horizontally when used with the Stereoly,
which will result in two vertical images. The camera should not be used
vertically.

Fig. 170 Stereoly Photographing
Unit for Stereoscopic Photography
with Hektor, Elmar, and Summar
50mm Lenses only

Fig. 169 Stereo Viewer,
on Stand, for 35mm Leica
Stereo Positives

Fig. 171 Stereo Slide Bar, for
Stereoscopic Photography when
making two separate negatives

250

Stereo

Taking Stereo pictures with the Leica is no more complicated than
taking ordinary pictures. The Stereoly is placed before the lens, given a
simple adjustment described in the instructions accompanying- each instru-
ment, and one is ready to take pictures. The exposure variation of the
Stereoly is almost negligible, if one considers the latitude of modern film
emulsions. To be sure, the exposure factor is not constant. It varies from
the requirement of an exposure fifty per cent longer with the lens set at
f:3.5 to an increase of some ten per cent only, when the lens is stopped
down to f :12.5. As a matter of general practice, it is recommended to take
stereo pictures with the lens stopped down to f :6.3 or f:9. Lens openings
larger than these do not yield sufficient depth of focus for stereo pictures,
while those smaller than f :9 are apt to cause vignetting of images under
certain conditions. The Stereoly unit does not by itself cause any unsharp-
ness of pictures, but to avoid pictures lacking definition and detail, so
important in stereos, all exterior glass surfaces should be kept scrupulously
clean at all times, and free from finger marks above all.

Filters for Stereo Photography

Filters may be used in connection with the Stereoly attachment if
they are in the standard Leica slip-on mount. They are simply placed over
the lens, and the Stereoly is attached over the filter. Since the aperture
of the lens cannot be changed nor can the filters be removed without first
removing the Stereoly from the camera, it is suggested that the lens be
operated always at the same stop when used for stereo pictures. Filters
should be used as judiciously as in any other form of Leica photography.
It should be remembered that filters, as their name implies, are not there
to add anything to the pictures, but merely to remove something that may
be objectionable. Frequent reference to the special chapter on this subject
may, we hope, result in a more reserved and more appropriate use of
filters in general.

In certain instances where special filters used for definite effects are
not available in Leica mounts, and cannot be made to fit on account of
their excessive thickness, they may be used (if available in pairs) by being
fastened to the front part of the Stereoly taking unit in such a way that
they completely cover the two front apertures. It may not be amiss to
say that when this is resorted to, both filters must be identical.

Sunshades and Film

Experiments have shown conclusively that stereo pictures secured with
the aid of sunshades were quite superior to those obtained without them.
They seem to be sharper, clearer and more brilliant and have a better defini-
tion throughout. The proverbial ingenuity of Leica users should find here
another field of application. The writers have used successfully two stand-
ard Leica sunshades of the inexpensive kind fastened to each end of the
Stereoly unit by means of scotch tape. On another occasion, a 10 inch length
of 1% inch black scotch tape wound all around the front edge of the
Stereoly, protruding about an inch, served the purpose admirably.

Stereoscopic photography with the Leica is so simple that it may be
said that there is actually no difference between this form of photography
and any other form of Leica photography, except for the accessories re-
quired. For this reason the selection of film, developer, filters, and other
factors should be made exactly as one would for any other form of work.
Fineness of grain is not more, but certainly not less, important than in any
other form of Leica photography. Careful handling of negative material
is just as imperative. Absence of scratches, abrasion marks, reticulation

251

and all other proofs of carelessness is just as important in stereo pho-
tography as it is, say, in portraiture.

Selection of film should be made in a similar way to that of ordinary
photography. Orthochromatic film of fine grain should be preferred by
beginners, and those who are not accustomed to the latitude and softness
of panchromatic emulsions. Those, however, who know and like panchro-
matic films will prefer them for stereoscopic photography just as they do
for other types of work,

It is quite feasible to produce direct stereo transparencies on negative
stock by reversal. For this purpose, the newest Agfa film, the Eeversible
Superpan is very much to be recommended. Generally, regular negative
materials of the modern type cannot be used for reversal on account of
their gray nonhalation backing. However, it should be realized that although
reversal as one of the simplest ways for securing transparencies, it is by
no means the most practical procedure: through reversal one loses the nega-
tive, and with it the only way for making additional prints. After reversing
a negative, one has nothing but that one positive on hand, and production
of additional positives, while not impossible, is difficult and rather compli-
cated. Even with the greatest care, positive films do get scratched and
damaged in handling and pulling through the Stereo Viewing Attachment.
Because of this fact, one should have the means of securing another positive
print easily and economically. All positive transparencies should receive
an adequate hardening treatment by any of the methods described in the
chapter dealing with this subject.

Stereo Color Pictures

As far as black-and-white photography goes stereo transpar-
encies represent probably the most realistic form of reproduction.
But natural color transparencies for stereoscopic viewing mark the
goal (at least at present) of realism. "With the advent of KODA-
CHROME, the new natural color film recently made available for
the Leica camera by Eastman Kodak Company direct color stereo-
scopic photography with the Stereoly Attachment is not only prac-
tical but extremely simple and easy. No color filters being required
for use with Kodachrome film, there being one type of film for day-
light and another for work in artificial light — there is no longer any
impediment to simply attaching the Stereoly to one's Leica, stopping
down the lens and proceeding to photograph in natural color as one
would to make black-and-white pictures. Kodachrome Haze filters,
if one wishes to use them for distant views, should be used according
to suggestions made on the preceding page.

The handling of Kodachrome films is described in a special chap-
ter of this volume (Chapter 14). No other special knowledge nor
equipment is necessary to secure excellent stereo transparencies in
natural, brilliant colors from the very first roll of Kodachrome film
used. The same roll of film can, of course, be used for both stereo
and standard pictures. After the film comes back from processing

252

Stereo

the respective frames are cut apart and mounted either for projec-
tion or for viewing in the Stereoly Viewing Attachment.

The emulsion speed of both types of Kodachrome Film has
recently been so substantially increased that perfectly exposed pic-
tures are easily obtained at the f :6.3 aperture recommended for work
with the Stereoly Attachment. The film is processed by Eastman
Kodak, the cost of processing being included in the original purchase
price of the roll. This should be welcomed by many miniature cam-
era workers as it relieves them of the necessity to put their color
films through a tedious and rather complicated procedure.

Protecting the Stereos

Stereo transparencies of any intrinsic value that cannot be dupli-
cated should be handled with particular care. Any stereo transparency
may be bound between two thin plates of cover glass and thus assured
comparative permanence and security from scratches, abrasion marks
and finger marks. This precaution would apply particularly to color
transparencies, where negatives are not available, since they are ob-
tained by means of reversal. For this reason, color transparencies
should be bound in glass as soon as they are dry and ready for viewr-
ing. One has the choice of binding them into individual frames, or,
better still, into strips of three frames each. Special cover glass plates
are available for this purpose, measuring 35mm x 120mm, and their
use cannot be too strongly recommended, not only for color transpar-
encies, but also for any black and white pictures wrhich are worth hav-
ing. In such bound form they become comparatively permanent and
most convenient to handle and to file.

While the Stereoly may be used for all forms of stereo photog-
raphy, both indoors and outdoors, it is primarily intended for work
without a tripod, for action pictures, landscape work, and all such
subjects as require rather short exposures. A somewhat simpler acces-
sory is available for stereo photography of still life, table top photog-
raphy, three color separation work, etc. This accessory is known as
the Stereo Slide Bar: a metal bar about 6 inches long with an en-
graved scale and slide mounted upon it. By means of a set screw
the slide may be placed anywhere along the bar. The Stereo Slide
Bar is firmly secured to a rigid tripod either of the field or table top
variety. The camera is fastened to the slide and one exposure is made
with the camera at one end of the bar. Then the camera is quickly
moved to a predetermined position at the other end of the bar, and

253

the second exposure made. Thus, the set of stereo pictures Is secured
upon two full frame negatives, which may be made either into trans-
parencies or prints. This method, while not as universal in its appli-
cation as the Stereoly, has certain advantages over the, other. The
separation of the two shots may be adjusted to suit any special re-
quirements, a separation up to 6 inches being available for special
effects. Any lens and any filter may be used for this type of work. The
two resulting pictures are larger than those available with the Stereoly,
but they cannot be viewed through the regular stereo viewing unit.

The Stereoly unit should not be used for photographing objects
less than 5 to 7 feet from the camera. Close range photography in-
troduces complications of parallax adjustment, since the optical axes
of the two prisms of the Stereoly are theoretically parallel, intersect-
ing one another at infinity. For this reason, photography of near
objects may better be accomplished with the aid of the Stereo Slide
Bar, into which the parallax adjustment may be introduced by careful
manipulation.

Using Two Cameras

There is still another method of stereo photography feasible with the
Leica camera, but for the present, it remains within the realm of experi-
mental possibilities, there being a lack of specific accessories for the purpose.
Such accessories would have to be produced by the experimentally minded
worker, conceived by his own ingenuity and adapted to his specific require-
ments. This new method is mentioned here just as an experimental possi-
bility for whatever it may be worth.

The method requires the use of two Leica cameras, each equipped with
the same type of lens. It makes little differences which two lenses are
chosen so long as they are identical. The experiment is available not only
to those fortunate members of the Leica fraternity who own two cameras
with lenses which are alike, but to any two friends who desire to pool their
equipment, work and experience for the purpose of achieving: interesting
results.

The two cameras should be mounted together upon some rigid mount
in such a manner that the bottoms touch, while the lenses face in the same
direction. In order that the respective lenses be on the same level, it is
necessary to have one of the cameras slightly higher than the other. With
the cameras placed in this manner, operating controls on the outside are
easily accessible. Such an arrangement is quite feasible since it so happens
that, with the bottoms of the two cameras touching each other, the lenses
are about 65mm apart. This provides the minimum separation. Greater
distances may be secured by placing strips of cardboard between the bot-
toms of the cameras, or an accurately prepared wedge of wood, in the
event that a parallax adjustment be required for special close range work.

Once these cameras are correctly assembled in a comparatively rigid
unit, their operation is simple and effective. Such an outfit actually exceeds
the Stereoly method in flexibility and adaptability for special work, such as
close-up work, more particularly since it permits the use of interchange-
able lenses, filters, and parallax adjustment.

254

Stereo

Each of the two cameras should be equipped with the Universal View
Finders, which also have the parallax adjustment, and exposures might be
made simultaneously, either by hand or by means of cable releases. A truly
de luxe method of operating the shutter releases would be provided by the
Automatic Release, available for the synchronized operation of releases of
the Micro Ibs*b Attachment, employed in photomicrography.

This method has distinct advantages over any other method of securing
stereo pictures and should be considered seriously by all desiring to obtain
stereos of a scientific nature. One of its potential advantages is the ease
with which the parallax adjustment may be made, an adjustment decidedly
essential for the correct viewing of small objects photographed at close
range.

Depending on the focal length of the lenses employed in this work,
the separate pictures will have some overlap, which will decrease with the
increased focal length of the respective lenses. At all events, such overlap
may easily be eliminated in making the prints or transparencies, either by
means of masking them or trimming them just prior to mounting.

Making of Stereo Prints

Regardless of whether the Stereoly attachment or the Stereo
Slide Bar, or the two-camera method has been used to make stereo
negatives, paper prints may easily be produced from any of them.
The prints may be of the contact type, but a much better job will be
secured by making enlargements.

Enlargements or negatives produced with the Stereoly attach-
ment are made on one sheet of paper, preferably of the glossy variety
for greater brilliance and better detail. Before a print is made, the
available stereo viewing equipment should be examined to determine
the correct size of the finished print. It will be found to be most
practical to enlarge the entire frame of the negative and trim it to
the required size afterwards. Since there is no sharp line of de-
marcation between the two halves of the print, they should be cut
in half carefully, or better still, left together unseparated, and thus
mounted on a piece of cardboard of a size conveniently accommodated
by the stereopticon.

In the case of two separate negatives obtained by the other two
methods, separate enlargements will be made. It is important that
both negatives be enlarged to identical size, with the enlarger in the
same position, using the same paper, developer and exposures. Fin-
ished prints should be trimmed only after careful examination and
tests made in the stereopticon. These prints should not be trimmed
by a rule of thumb to include similar areas. It must be remembered
that each picture has been secured from a different view point and
there is a most decided difference in each print which has resulted in
the three-dimensional aspect of a view. This point is mentioned to
prevent arbitrary cropping of finished prints.

255

§)

> 3

o3 *o

§ I

256

A. L. LUGN, Ph. D. CHAPTER 13

Every amateur photographer has at one time or another come
upon landscape scenes, interesting architectural settings, interiors of
large buildings, groups of people and no doubt many other interesting
photographic subjects which are beyond the limitations of the ordinary
hand camera. Keen disappointment may have been experienced in
an attempt to photograph these subjects from a distance sufficient to
include the entire horizontal length of the scene within the long
dimension of the average hand camera negative by use of the short-
focus lens. When such a long picture is finished, the landscape is
stretched across the print in a thin line with approximately ninety
per cent of the print area a total waste. The details, also, are com-
pletely lost in their minuteness. At one time or another, every amateur
has probably wished for a panorama camera which would combine the
expanse of the view with the details of the scene.

The Leica camera, with its large negative capacity and its ability
to take pictures in rapid succession has brought panorama photography
within easy reach of the novice. Chance and guess work have been
eliminated from the operation by the simplicity and dependability of
the accessories required. Weighing but a few ounces, they consist of
the following units :

1. A Ball Jointed Tripod Head — for leveling of the camera and for
locking it in that position.

2. Special Angle Bracket — required for centering the lens over the
pivotal point and for using the camera vertically.

3. A Spirit Level — fitting into the clip of the camera for horizontal
pictures, or the clip of the Angle Bracket for vertical pictures.

4. Cable Release — serving to avoid jarring of camera and disturbing
its position.

5. Panorama Tripod Head— with any of the interchangeable gradu-
ated rings, depending on lens used. Each of these rings has two
sets of 'graduations : one for horizontal, the other for vertical use
of the camera.

257

Fig. 373 Accessories for Panorama Photography:

Ball Jointed Tripod Head, Spirit Level, Angle Bracket and Panorama Tripod Head with
interchangeable graduated rings for various lenses

6. Universal View Finder — if any but the 50mm lens is used.

Obviously, a good rigid tripod is essential for this work in order to
permit the camera to be rotated around a pivotal point, for taking sec-
tion views of a complete circle or of any portion of it.

Composing the Panorama

Photographs belong to two general classes: those intended as
records of objects or incidents, and those whose purpose is to render a
pictorial interpretation of things, people and incidents. Panorama
photographs usually belong to the first classification, but they may,
if desired, be used pictorially. Photomurals, for instance, frequently
present opportunities of a strictly pictorial nature for panorama views.

In the case of record photographs, pictorial composition is not
important and, therefore, a symmetrical picture is probably the
simplest and most satisfactory. If a pictorial panorama is desired, the
same principles of good design and composition which are employed in
other forms of photography must apply. The chief difficulty will be
found in maintaining unity. In a picture several times as wide as it
is high, the eye covers too great space in one direction and is likely
to fix upon many irrelevant details without being led to any particular
center of interest. To avoid this and to permit the eye to travel
smoothly from one end of the picture to another, the position from
which the picture is taken should be carefully chosen.

Unimportant and undesirable details tending to distract from the
main interest of the picture should be carefully eliminated. Where
this is impossible, undesirable details may be dispensed with by means
of paper negatives, enlarged negatives, obtained by reversal and such
other means of control as are available for other photographic ren-
dering. The most pleasing panoramas are those which do not cover

258

Panorama

too great an- are of the circle, preferably no more than can be viewed
from one position without turning the head.

Panorama Tricks

Certain kinds of tricks or stunts, possible with the Leica and
panorama accessories, will readily suggest themselves to the reader.
One or more persons or objects may be repeated several times in a
panorama with a continuous background. Other effects may be ac-
complished with the camera attached to a universal tilting tripod head,
by means of the angle bracket, in either horizontal or vertical posi-
tion, making it possible to panoram vertically or at an angle. A tall
tower or the details of a tall building may be photographed by
panoraming at an angle, starting at the lower left and moving upward
to the right. Interesting panoramas of tall buildings may be made in
this way. This type of shot is best adapted to city scenes and should
be very useful in some kinds of news or advertising illustrations. In
making vertical panoramas of tall buildings, photographing them
from anywhere but street level should be avoided as it will result in
"bellying out" of the portion of the building nearest the camera level.

Fig. 174 Complete Panorama Out-
fit Assembled for Horizontal Pic- Fig. 175 Complete Panorama Out-
tures fit Assembled for Vertical Pictures

259

me pictures

The nature of the subject, its size and relation to position of
camera should determine the choice of the lens used. The short focus
lenses, such as the 35mm or 50mm are best adapted to work in interiors
where sufficient room for backing the camera is not available. The
longer focus lenses may be used for distant outdoor scenes where it is
necessary to reach out for details of mountain ranges, forests, gla-
ciers, etc.

To take a series of negatives for panorama pictures, the first thing
necessary is to select a suitable position for the camera. This will be
determined by the nature of the subject, the purpose of the picture,
available space, and composition desired, as outlined in previous para-
graphs. The camera is set up on a sturdy tripod, attached by means
of the panorama head and held either in the vertical or horizontal
position. The former is to be preferred since it yields a higher picture
with a somewhat better proportioned finished job. The camera should
be perfectly level. If it is not, the sections, when trimmed, will bow
up or down at the ends, resulting in a certain amount of distortion
when cut to a rectangular shape.

The next step is to determine the farthest and the nearest points
in the picture which are to be in sharp focus. To re-focus between the
pictures of a panorama is impractical since this alters the relative size
of the pictures and they win not match up. The lens stop, therefore,
must be adjusted for the necessary depth of focus before the first pic-
ture is taken. The depth of focus scale (on every Leica lens) should be
utilized for this. The finished panorama is a series of separate
prints, joined so as to look like one large print. The negatives
therefore should be absolutely uniform. In order to obtain such nega-
tives, a dependable exposure-meter should be used and consulted before
each separate exposure. It is important, too, that all exposures in-
tended for one panorama be taken on the same roll of film to assure
identical treatment in processing. Make sure that sufficient film is in
the camera before starting to take a panorama; reloading the camera
during a series of shots will most assuredly upset the job. After the
exposures are made, the film should be processed and handled through-
out in the same manner in which it would be handled for any other
Leica photographic work.

At times uniform negatives cannot be obtained. Such may be the
ease in a large interior illuminated with artificial light. In such cases,
the differences must be compensated for in the making of prints.

260

Panorama

Making the Print

The technique of making prints for a panorama picture is not
much different from that employed in making enlargements generally.
The points of difference are : 1. Once the size of the final print has been
decided upon and the enlarger set and focused, the latter should not
be changed in any way until the last print of the series is made.
2. Areas of prints adjoining each other must match in tone values.
This is achieved by maintaining a uniform temperature of developer
throughout, using paper from the same package, giving the same ex-
posure and development time, if the negatives are of uniform density.
If they are not, it may be necessary to vary the exposures according
to results obtained by means of test strips. A certain amount of
dodging or shading — holding back or printing in, may be required for
best results. It is advisable to make several prints of each section and
to match the best ones for assembling the finished picture.

Assembling and Mounting the Finished Panorama

After the prints are made, they must next be matched, trimmed,
and mounted. A suitable cardboard should be selected according to tEe
photographer's tastes and desires, just as in mounting any other kind
of print. Paste or dry mounting tissue may be used, but the writer
has found dry mounting tissue to be the more satisfactory. Paste
causes the prints to expand, not always uniformly, and they contract
on drying. This almost invariably results in the prints pulling apart
slightly, leaving a small but undesirable crack between the sections.
This may be avoided with dry mounting tissue, and with careful
manipulation, perfectly printed sections may be joined with scarcely
a line showing. However, the most carefully mounted prints some-
times pull slightly apart in damp weather due to the expansion of the
mounting board.

Since the trimmed edge of the paper is white, it is advisable to
darken the edges with a pencil where dark areas of adjoining prints
meet. If white or light-colored board is used for mounts, it should
also be shaded with the pencil to match the print along all lines where
prints meet. This is a small, but not unimportant, detail.

A sheet of dry mounting tissue is tacked to the back of every
selected untrimmed print of the panorama. The overlap at the sides
of each sectional print is carefully trimmed either on a sharp and truly
square trimming board, or by means of a straight-edge and a knife or
razor blade. When this is completed the details of adjoining sections
are made to match. The prints are then placed on the table matched,
ready to be put together. An accurate outline of the finished print is

261

then drawn lightly with pencil on the mount, squaring it up, if neces-
sary with a straight edge or a T square. Each sectional print is fitted
into its position on the mount, top and bottom receiving the final trim.
They are then ready to be mounted.

A pencil mark is made lightly on every sectional print and on the
mount, indicating its final position on same. The edges of each print
should be shaded with pencil at this point as well as the mount proper
at points where two prints join. It is best to begin dry mounting the
print by starting with the center section. The sections should be
placed on the mount one at a time, lightly tacked with a tacking iron
to the mount and then placed into the dry mounting press for about
15 to 30 seconds. If this is done carefully, no overlapping will take
place. It is possible to use an electric iron for dry mounting, but the
manipulation must be deft to avoid scorching and marks.

For permanence, and because of the amount of care and work
involved in the making of such a print, it is best to frame it under
glass on completion. If matt or semi-matt paper is used for the finished
print, satisfactory preservation may be obtained by spraying the fin-
ished print and the entire mount with one or two coats of clear lacquer,
which will protect it against dust and dirt. Thus protected, the print
may be washed with a damp cloth if a good grade of lacquer has been
used.

There are other ways of mounting prints, rubber cement or
vegetable paste being quite as efficient, and frequently more con-
venient. Not many amateurs own a dry mounting press, and they
may prefer these other methods, which are described elsewhere in this
volume. (See chapter on Photomurals for mounting with vegetable
paste, and chapter on Enlarging and Printing for mounting with,
rubber cement.)

Fig1. 176 Hall of Elephants — Nebraska State Museum — A Panorama Leica
Picture Made by Dr. A. L. Lugn

How the picture was made... 50mm f:3.5 Elmar lens with diaphragm set at f:12.5, 2 min-
ute exposures, DuPont Superior Film. Seven separate negatives used to make the complete
panorama view.

262

HENRY M. LESTER

ROWLAND S. POTTER CHAPTER 14

A few months ago the Eastman Kodak Company placed at the
disposal of Leiea workers a new medium for direct Color Photography
which eclipses most existing standards and results achievable hereto-
fore in this exciting field. Luckily for Leiea workers, the original
designer of their camera selected the 35mm film for its negative
material, and the new film is available at present in this size only.
The new medium — KODACHROME FILM — was offered to Leiea users
after having been successfully used for over fifteen months in the
field of 16mm cinephotography. Vast improvements made in the
material proper, as well as in its processing, resulted in a film which
leaves little more to be desired of it as far as emulsion speed, color
rendering qualities and general flexibility are concerned.

As matters stand now, it is extremely simple to obtain one or a num-
ber of natural color transparencies; in fact, almost less difficult than to
produce a good black and white negative. While subsequent production
of color prints on paper is somewhat more complicated, it is nevertheless
quite feasible through one of the two methods:

1. The DEFENDER CHROMATONE.

2. The EASTMAN WASH-OFF RELIEF.

By far the simplest part of Natural Color Photography is the making
of color transparencies on Kodachrome film. Available in daylight loading
magazines, ready to be inserted into the camera, in lengths sufficient for
18 exposures, Kodachrome need only be exposed correctly, sent to Eastman
for processing (the cost of which is included in the original price of the
roll), and it is returned in the form of excellent positive transparencies —
sharp, grainless, free from color fringes, patterns or screens (shortcom-
ings of some of the other color materials).

Kodachrome Film

Based upon the subtractive principle of color photography, Kodachrome
reproduces natural colors as faithfully as seems possible at present. The
separation of colors is secured in an unusual but extremely efficient man-
ner: within the body of the emulsion itself. This is accomplished by coat-
ing the film support five times. These five layers consist of three coats of
color sensitive emulsions, which are separated by two coats of plain gelatine.

263

Each of the three coatings of emulsion is selectively sensitized: that adjoin-
ing the film support is red sensitive; the center coating is green sensitive;
and the outer, top, coat is sensitive to blue-violet. The two layers of plain
gelatine prevent the sensitizers of emulsions from straying away from
their respective coatings. The all-over thickness of these five layers is no
more than that of the emulsion of ordinary black and white negative
material.

When an image is focused upon Kodachrome film, some part of the
picture is formed in each of these three layers, depending upon the color
of the subject: red colored objects in the picture are recorded by the bot-
tom, red-sensitive layer; green colored objects by the center, green-sensi-
tive layer; and blue colored objects by the top, blue-violet sensitive layer.
After the film is processed by the reversal method, each of the three coats
of selectively sensitized emulsions is dyed with color complementary to its
original sensitivity. The bottom, red-sensitive emulsion is dyed blue-
green. The center, green- sensitive coat is dyed red (magenta). And the
top, or blue-violet sensitive layer is dyed yellow.

During the processing the metallic silver image is dissolved and thus
removed, leaving a pure dye image reproducing beautifully all colors of
the original.

Two Types of Kodachrome

Because each of the three coatings of emulsion can be sensitized select-
ively, Kodachrome Film can be made for practically any purpose and of
varying degrees of sensitivity in any of the spectral color regions. Accord-
ingly, two types of Kodachrome Film are available to suit the two kinds
of illumination: daylight and artificial light.

The Kodachrome Regular (K135) has an emulsion which is designed
to produce correct color rendering in daylight without any filters or other
accessories. However, a special Haze Filter will improve the results if
used under certain conditions. Ultra-violet light which may occur in
extremely distant scenes, snow scenes and at high altitudes, will record
on the Kodachrome Film as violet. To correct this, the Kodachrome Haze
Filter should be used (it requires no change in exposure). The same
filter will also improve color rendering by imparting more warmth to the
tones of scenes and people photographed on a gray day or in the shade.

Kodachrome Regular can be used in artificial light, provided a Koda-
chrome Filter for Photoflood (blue) is placed in front of the lens. This
filter changes the quality of artificial light to that of daylight by reducing
the excess of red prevailing in artificial light. There being a special type
of film available for artificial light, the use of the Regular film should be
restricted to daylight work. The filter generally has an exposure factor
of 4x, which calls for too long exposures.

The Kodachrome Film Type A (K135A) has an emulsion especially
corrected for use with artificial illumination so that no filter whatever is
needed to obtain correct color rendering. Specifically, the color sensitivity
of this film is very accurately adjusted for light of Photoflood and
Photoflash bulbs. No other bulbs should be used if correct color rendering
is desired. High-wattage tungsten bulbs are apt to make the pictures too
red. The "daylight" or blue bulbs should not be used because they will
make the pictures too blue. Similarly, arc lamps that produce light

264

Color Photography

approaching- daylight in quality will make the pictures too blue on Type A
Film. Primarily intended for work in artificial light, the Type A Film
is not recommended for daylight, for which purpose it can, however, be
used in connection with the special Type A Kodachrome Filter for Daylight,
which is reddish-yellow to change the quality of daylight to artificial light
by reducing the ultra-violet and the blue portion of its light.

Exposure

Every roll of Kodachrome Film is accompanied by very specific recommendations for
exposures. The most satisfactory results will be secured by following these instructions to
the letter. Color photography requires much more critically correct exposures than black-
and-white work. Generally the latitude of color film is much more limited than that of
black-and-white films (about 1/3). Such variables as climatic conditions, to which Koda-
chrome Film is rather sensitive, geographical latitude, accuracy of shutter speed and lens
diaphragm, may tend to produce some over or under exposures. Until all such variables
are fully under control it may be best to take three pictures of each scene: one exposure
following the manufacturer's recommendation, one at twice, and one at half the recom-
mended exposure. Intelligent and judicious use of a good exposure meter of the photo-
electric variety should prove very valuable for getting consistently good results with
Kodachrome Film. However, due to variations in color sensitivity of various meters,
even those of the same make, they should be carefully checked and calibrated against
actual results. The best way to calibrate one's meter is to make a few exposures strictly
in accordance with manufacturer's recommendations, while at the same time securing
a reading with one's own exposure meter. If both indications coincide and the resulting
pictures are right the meter is correctly calibrated. Slight differences can be adjusted
by resetting the emulsion speed from that recommended by the exposure meter to that
corresponding to exposure setting which secured a well exposed picture.

For general guidance, subject to variations, it may be said that the Kodachrome Films
can be rated as follows :

KODACHROME FILM: Weston Scheiner Din

Regular K135 (daylight) 8 18° 11/10

(Photoflood light)* 3 14° 7/10

Type A. K135A (Photoflood light) 12 20° 13/10

(daylight) f 8 18° 11/10

* with the Kodachrome Filter for Photoflood.

f with the Type A Kodachrome Filter for Daylight.

Illumination

Color photography has its own requirements of illumination which are quite different
from those applying to black and white work. In the latter, the differentiation of form,
lines and planes is produced by contrasts of brightness and shadows cast. In color woric
much less contrasty illumination is required because the "tones" and gradation are pro-
duced by color. In outdoor work best results are obtained with the sun approximately
behind the camera. It should be remembered that increased exposures are required if the
sun is to one side of the camera, (almost double), and still longer exposures when the
camera is facing the sun (about four times normal).

For indoor work with Photofloods a flat "flood" type illumination should be provided
to avoid shadows as much as possible. Assuming that lights are being placed on both
sides of the camera, most pleasing results will be secured when some 60% of the entire
amount of light will come from one side, while about 40% from the other.

Several points should be remembered when arranging lights for indoor color photog-
raphy. All Photofloods should be new. Each bulb should be used in a suitable reflector,
the Kodafleetor type or the Kodak Handy Reflector providing the least expensive and most
efficient form. Each reflector should be directed upon the subject so that the full amount
of light reaches it. When working in artificial light, daylight should be completely ex-
cluded ; otherwise the pictures will show too much blue in those portions which were
illuminated by daylight.

Instructions accompanying each roll of film contain a complete exposure table for use
with Photoflash bulbs, which when followed to the letter with the aid of a tape measure
will assure perfect results, where the use of Photoflashes is preferred to Photofloods, as
in action shots, photography of children, pets, etc.

265

Viewing and Projection

Though a few photographers bemoan it, it seems particularly fortunate that the pro-
cessing of Kodaehrome Film is attended to by The Eastman Kodak Company. It must be
remembered that the film consists of reversed images, there being: no negative. Subsequent
manipulations called for in the making of color enlargements require absolutely perfect
transparencies, free from scratches, blemishes and any traces of handling. The Kodachrome
transparencies as they arrive from the processing laboratory are very carefully packed and
as a rule reach us in excellent condition. They should be immediately and permanently
protected against any possible damage which may result if they are put in an enlarger,
projector, or Stero Viewer. Depending upon the use to which they are put, they should
be suitably mounted between glass. A number of mounts, masks and mats are available
to meet adequately any possible requirements. The Kodachrome 35mm. transparencies can
be mounted either in standard lantern slides (3*4" x 4") or Leica size lantern slides
(2" x 2") or into strips of three exposures each for Stereo Viewing (bound between special
cover glass measuring 35 x 120 mm, available through E. Leitz, Inc., New York). In
addition to masks required for mounting between glass there are hand-viewing mats avail-
able in horizontal or vertical arrangement.

Under no circumstances should Kodachrome transparency strips be used directly in
projectors or enlargers because scratches and abrasive marks, impossible to prevent, will
promptly ruin the usefulness of the valuable strip. At the moment of writing no color
duplicates are possible. Black and white copies can be made on panchromatic negative
material by contact printing. From such duplicate negatives subsequent black and white
enlargements can easily be made.

Black and White Enlargements From Kodachrome

Black and white enlargements from Kodachrome transparencies can easily be
secured by projection upon Eastman Kodak Direct Positive paper. This is a reversible
material, very easy to handle and its only drawback is that the Direct Positive paper is
somewhat slower than the usual projection papers. One can secure an inexpensive com-
plete outfit for direct positive work either for sepia effects or for black and white effects
by ordering same through any Kodak dealer. Enlargements up to 5 x 7 can easily be made
but if 8 x 10 enlargements are wanted a photoflood bulb should be used in the enlarger.
One should be tempted to make black and white enlargements from Kodachrome trans-
parencies for they are free from grain and have excellent definition.

It should be remembered when making enlargements upon direct positive paper that
the Kodachrome film must be placed in the enlarger with the emulsion away from the
lens to assure that the image will not come out reversed from right to left.

The greatest enjoyment can be derived from natural color transparencies by viewing
them in the form of brilliantly projected pictures. There is, however, a keen desire on the
part of photographers to make color prints, a desire which can now be gratified. The
making of prints from Kodaehrome transparencies resolves itself into two main parts.

Three Color Separation Negatives

The most critical and difficult part of the procedure is the production
of three negatives from the Kodachrome positive transparency, in such
a manner that each of these negatives records details of one of the three
basic colors as they were separated originally within the body of the
emulsion of the Kodachrome Film. This is accomplished by projecting
fche Kodachrome positive transparency by means of an enlarger upon
panchromatic negative material, first through a green filter, then through
a red filter, and finally through a blue filter. These negatives are made
by three separate exposures upon three separate panchromatic negatives
of any desired size. The filters required for this are of the standard
three-color separation filter set consisting of A filter (25) B filter (58) and
C-5 filter (47).

The respective densities of these three negatives will have to be such as to produce
good color balance later in the making of the paper print. To secure this balance two
conditions should be met. The enlarger lens should be exceptionally well corrected for
color. A Photoflood bulb should be used in the enlarger, or a blue filter (daylight)

266

Color Photography

should be placed between the bulb and the lens of the enlarger. The exposure factors
of the three filters used should be definitely established with regard to both light source
of the enlarger and film used before exposures are made. Thus, for instance, if a film
as Eastman Kodak Panatomic is used for making the negatives, the respective filter
factors will be as follows: A Filter — 3, B Filter — 8, and C-5 Filter— 12, if tungsten light
is used. For other films, filter factors referring to artificial light offered on page 95
should be consulted, or obtained direct from the manufacturer whose film is used.

It should be remembered that the original Kodachrome transparency should be
placed in the enlarger with the emulsion side facing away from the enlarger lens. This
will assure correct placement of subject on finished color prints.

The negatives are then developed according to recommendations of the manufacturer
to secure full detail and gradation. Each negative is carefully identified by a proper
mark referring to the filter it was made with. The negative made through the red filter
will then become the blue printer ; that made through the green filter, the red printer ; and
the one made through the blue filter, the yellow printer.

Making Separation Negatives in the Camera

The Kodachrome film is undoubtedly the quickest and simplest method of obtaining
the original color positive. Requiring no accessories "in the field" it can be broadly
applied to action photography, and photography of living and moving objects. At times,
however it may be desirable and possible to make three
separate negatives of the same object. This is done sim-
ply by making three exposures on the same Panchromatic
film, one exposure through each of the standard "Wratten
three color separation filters A, B and C-5. A set ol
these three filters mounted in a rotating segment is pro-
duced and distributed by the Chess United Co. of New
York. This combination set is known as the "Trichromatic
Separation Filter," is mounted directly over the lens
and each of its three filters moved into taking position Trichromatic Separation
as required. (The same filter can also be used in con- Filter for use on Cam-
nection with making three color separation negatives by era or Enlarger Lens.
projection in the enlarger.)

The exposure factors of the three color separation filters vary depending on the nega-
tive material used. They will be found in the filter factor table on page 95. As a matter
of convenience the following filter factors for DuPont Superior Film are given :

Daylight Photoflood Mazda

A 95 4

B 5 6 6

C-5 6 10 13

It seems almost superfluous to point out that the camera must be rigidly supported
for the making of three color separation negatives. A neutral density scale consisting of
step gradations of white, grey and black, sharply outlined, should always be placed in a
corner of the picture (so as not to appear later in the finished print but to appear on
every negative). The scale must be illuminated in the same manner as the subject and
should be sharply in focus to serve not only as a means of comparing the density of the
negative but also as a means for registering the three prints in superimposing them.
When the negatives are developed and dried they should be marked along the edge with
good water proof India ink as follows: B for the negative taken through Red filter for
blue color ; R for the negative taken through green (to be colored red) ; Y for the negative
taken through blue filter (to be colored yellow) .

The color balance of the final prints will depend upon the care and relative correct-
ness of exposure used in making the original black and white negative in the camera, or
of the separations made from the Kodachrome positive. If correct exposure has been
given the neutral density scale lef erred to will have the identical tone value in each
negative. If the original negatives are not correctly exposed, it may some times be pos-
sible to make a slight compensation by varying the exposure during subsequent manipula-
tions, but the results will not be as satisfactory as those originating from correctly bal-
anced negatives.

The problem of securing proper balance of densities in the three-color
separation negatives requires considerable experience before satisfactory

267

results are obtained and a good deal of experimental work will have to
be done before the proper technique is acquired. However, once a set of
satisfactory three-color 'separation negatives is available, one may proceed
to make color prints by either of the two methods outlined below.

Defender Chromatone Process

For Natural Color Photographic Prints

All manipulations involved in the Defender Chromatone Process are
very simple, and little difficulty should be experienced by the Leica worker
who is already familiar with the developing and toning technique. The
process is based upon the principles of three-color photography of the
subtractive type. Briefly, the process involves the superimposition of
three transparent positive prints: one dyed yellow, another magenta, and
the third blue-green — all mounted upon a white background, the finished
product resulting in a picture in natural colors. The original photograph
may be taken either by direct color film, such as Kodachrome or three
separate negatives can be made by direct photography through green, red
and blue filters. When the original color photograph has been made on
Kodachrome, it will be necessary to make three color separation negatives
as described above from which subsequently Chromatone color positives are
made.

White light is a mixture of all known colors. White is not an absence
of color, but on the contrary it is the sum total resulting: from the
presence of all colors. To show the presence of the components of light we
can pass a beam of this white light through a glass prism with the result
that the colors are separated into the spectrum: violet, blue, bluish-green,
green, yellow, orange and red. Each of these spectral colors is a true
color which cannot be broken down or separated into other colors by any
known methods.

For practical purposes, the spectrum may be considered divided as shown in the
following: diagram:

I
1

1
|

Blue-
Violet

| Green
1

1
1
1

Red

\400 500 ^yV^ 600

709/

^ v^

Bluish-Green Orange

The color of any object is due to the color of that portion of the incident light which is
reflected from its surface. The other colors of the incident light that are not reflected
are absorbed by the object.

It is commonly known that any color can be reproduced by mixing varying quantities
of blue-violet, green and red colors. Therefore all three-color processes are based on
photographing separately the primary colors: red, green and blue. In the case of Koda-
ehrome this is accomplished within the body of one composite emulsion while in three
color separation negatives made in the camera, or by projection, this is done by three
separate exposures made through red, green and blue light filters respectively.

268

Color Photography

Making the Actual Color Prints

The principle of color prints is based upon considering the white paper
stock upon which the print is being built up as the light source. This
white paper stock reflects all colors of the spectrum. From each of
the three separation negatives secured either directly through the camera,
or by projection from a color transparency like the Kodachrome, posi-
tive prints are made upon a special stripping film (Chromatone Print
paper) which is exposed and handled similarly to projection paper.
The collodion emulsions of the Chromatone Print Paper are stripped off
their base, toned to the proper color, which is complementary to the color
of the filter through which its respective negative had been made, and
superimposed over each other upon the white paper backing. The comple-
mentary color of red is blue-green; it transmits both blue and green,
absorbing red, being therefore white minus red. The complementary color
of green is blue red or magenta; it transmits both the blue and red, and is
therefore white minus green. The complementary color of blue is red,
green or yellow; it transmits both red and green, and is white minus blue.
When all color prints are superimposed upon the white mounting paper,
each print will thus subtract from the white of the paper all the portions
of the original which were not blue, green or red, according to the respect-
ive light filters through which its negatives were taken. Such superimposed
prints if correctly registered will give a print in natural color.

The black and white Chromatone prints are thoroughly fixed and washed for at least
15 minutes in running water. In the fixing bath the gelatin emulsion can be stripped
or separated from the paper backing. The stripped emulsions should be handled with
reasonable care to avoid formation of kinks. The next step is to tone each film, in its
respective Chromatone toning solution.

Toning the Separation Positive

The stripped off black and white positive films which are intended for the Red and
Blue images are placed together in one tray and the Red and Blue toner-A made up
according to the formula sheet accompanying the materials is poured over. They should
remain in the A solution for at least 15 minutes thoroughly agitated until all of the black
silver is removed. When these prints are thoroughly toned they will appear as a light
greenish blue image. They are then placed in running water and thoroughly washed
for about 10 minutes. It is essential that hands be kept clean at all times to avoid con-
tamination of various solutions.

After this washing, the film to be toned is placed in the Red toner B, and allowed
to tone for about 10 minuf-es. The solution is then poured off for use a second time,
and the print is immersed for three minutes in a 15% hypo solution (granular or rice
hypo: 2% oz. (70 grams) — distilled water 32 oz. — (1000 cc.) (Do not use acid fixing hypo).
It is then washed for about 15 minutes in running water.

Similarly, the film to be toned Blue-green is placed in the Blue toner B and allowed
to remain for about 10 minutes, after which the toner is poured off for use a second
time, and the print immersed in a tray of weak hydrochloric acid solution for about on*1
minute. Use one part of diluted solution hydrochloric acid CP : 16 oz. (500 cc.) — distilled
water 48 oz. (1500 cc) with one part of water. The print is then thoroughly washed
in running water for about 10 minutes after which it is placed in a tray containing
standard hypo solution (see above) until greenish tones have changed to blue. It is
then washed for 20 minutes in running water.

The Yellow toning solution (Yellow Toner A) is supplied in two solutions, equal
parts of which are mixed foi one. The print to be toned yellow is immersed in this
solution for about 15 minutes. This work may be carried on simultaneously with the
blue and red toning operations, separate trays being used. At the end of about 15
minutes the solution is poured off into a graduate and 10 cc (3 drams) of standard hypo
solution is added to every 50 cc (2 oz. ) of working solution, and thoroughly mixed. Next
wash the print for 2 or 3 minutes in running water, or in one complete change of water,
return it to the tray and pour the solution back on the print. This operation should be
done quickly, and the tray should be vigorously rocked for about 1 minute to prevent

269

any streaking of the yellow image, The print is now allowed to remain in the solution
for about 3 minutes, after which the solution is discarded, the print washed for a minute
or two in clear water, and then immersed for about 1 minute in a solution made up of
standard hypo solution — one part, water three parts. Do not keep the print longer than
one minute in this solution as the image at this stage is slightly soluble in hypo and
highlight detail may be lost thereby. Wash the film immediately for not _less than 20
minutes in running water. The yellow image, after thorough washing:, is immersed for
about 2 minutes in the Yellow toner B, and then washed in running: water for -about 20
minutes. It is then ready for assembling.

The three-color images are now registered on a gelatin coated paper (Chromatone
Backing- Paper) which has been previously soaked thoroughly in water. Lay the backing:
paper gelatin side up, on a clean ferrotype tin, clean glass or Masonite tempered hard
board, or on any flat waterproof surface. The Yellow image is placed first on the paper
and squeegeed firmly into place, emulsion side down, and allowed to remain for a few
minutes. The Red image is then placed on top of the Yellow, pushed carefully into
register, squeegeed lightly, the register checked, and adjusted if necessary, and the Bed
image squeegeed firmly into place. If at this point the two images do not appear exactly
in register, the Red sheet may be peeled off carefully, re-moistened and registered again.
It will be found easier to register the Eed and Yellow images if they are viewed through
a light blue filter.

The Blue image is then superimposed upon the other two, precisely as described above,
completing the color print ; all prints emulsion side down.

The print is now allowed to remain in the air for about 10 minutes until the surface
dries to some extent. Next, the damp print should be trimmed so that the edges of the
collodion layers are flush. It is then placed on a piece of rigid, hard waterproof material.
Masonite Tempered Hard Board is admirably suited for this purpose.

Ordinary Kraft gummed tape is moistened and the damp print fastened to the board
with this tape overlapping the print about 3/16" on all four edges. Do not have the
gummed tape too wet or the gum will ooze between the print and the board, making it
difficult to remove the print.

The print will dry rapidly, stretched absolutely fiat. It can be loosened from the board
when dry by carefully inserting a sharp knife through the tape under the edge of the
print and running it around the print.

Chromatone prints, ordinarily processed, dry with a high gloss and great color
brilliancy, which is considered desirable for illustrative and commercial work.

A MATT finish can be obtained by rubbing over the glossy surface with fine dry
pumice powder. If the finished print is given a coat of good matt lacquer applied with
an air brush, varying degrees of matt finish can be secured.

To obtain rougher surfaces, any of the regular rough textured papers, such as
Defender Veltura Q, can be used instead of the glossy base paper when assembling the
print. Simply fix the paper, without exposure and thoroughly wash it.

A very interesting detailed description of the Defender Chromatone Process, its
principles and practical application is offered in a booklet that should be secured from the
Defender Photo Supply Co. of Rochester, N. Y.

The above described Chromatone Process of making color photographic
prints is one in which color images are formed on three transparent media
which are permanently superimposed upon paper, forming a print consist-
ing of a number of layers.

Wash-off Relief Process

Another method, in which relief images are formed on transparent
supports and dyed with water soluble dyes, and in which only dye images
are transferred to paper, known as the Eastman Wash-Off Belief Process
is offered to our readers. This comparatively new but thoroughly tried
process is readily mastered.

The Process in Brief

For the Eastman Wash-Off Relief Process of printing in natural colors, three-color
separation negatives are required. These are employed to make prints, by contact or en-
largement onto Eastman Wash-Off Relief Film. In either method of printing, the ex-
posure is made through the support of the relief film. Positive silver images are first

270

Color Photography

developed in the relief films, and are then bleached in a bichromate solution. This bleach
renders the gelatine of the photographic emulsion insoluble in the regions of the silver
image. Then, by washing in warm water, all of the soluble gelatin is removed, and relief
images in hardened gelatin are left adhering: to the supports. These are fixed in hypo
and thoroughly washed. The three relief images are then dyed in the Eastman Three-
Color Printing Dyes, A, B and G. The dyed positives may be superimposed in register to
form a three-color transparency, or they may be used in the imbibition transfer process to
make three-color prints on paper. To transfer the dyes to paper, each dyed positive is
squeegeed in turn onto a wet paper bearing a mordanted gelatin coating. A natural-color
print in ti'ansparent and stable dyes is thus produced.

The Negative

Three-color separation negatives are made directly from the subject
(or from Kodachrome positive transparencies as described earlier)
on Wratten & Wainwright Panchromatic Plates, Eastman Portrait Pan-
chromatic Film, Eastman Super- Sensitive Panchromatic Film, Eastman
Commercial Panchromatic Film, or Eastman Panatomic Film through
Wratten Filters, A, B, and C5 (Nos. 25, 58 and 47 respectively).

The negatives should he exposed with clue regard for the filter factors
corresponding to the light source employed, and all of the plates or films
must be uniformly developed. The inclusion in the subject of a scale of
greys near an edge of the field assists greatly in obtaining correct exposure
and development of the negatives, or in making suitable adjustments in
Ihe printing in case slight errors of density or contrast are found in the
negatives. If the set is correctly exposed and developed, any given step
on a scale of greys should have the same density in each of the three
negatives. The contrast or "gamma" for the scale of greys is preferable
0.8 to 1.2.

Step-by-Step Procedure of the Printing Process

Making the Relief Positives

1. Print by contact or projection through Wratten Filter No. 35 onto three Eastman
Wash-Off Relief Films, exposing through relief-nlm supports.

2. Develop 5 minutes in Formula D-ll at 65°F. (18°C.).

3. Wash 10 minutes in running water at not more than 70°F. (21°C.).

4. Bleach completely (about 2 minutes) in Solution R-10 at 65°F. (18° C.).

5. Develop 4 minutes in water at 110°F. (43°C.).

6. Fix 1 minute in Bath F-24.

7. Wash 5 minutes in running water.

8. (Optional) Bleach brown stain by bathing 1 minute in Permanganate Reducer R-2.

9. (Optional) Wash 3 minutes in running water.

10. (Optional) Clear by replacing in Bath F-24 for 1 minute.

11. (Optional) Wash 5 minutes in running water.

12. (Optional) Dry.

Dyeing1 the Reliefs.

13. Dye reliefs in solutions of Dyes A, B and C for 30 minutes.

14. Rinse in dilute acetic acid of concentrations given.

15. Superimpose dyed reliefs for inspection.

16. If necessary, give corrective treatment.
Finishing Transparencies.

17. Dry Films.

18. Varnish, if desired, and dry.

19. Register films in superposition.

20. Bind films between cover glasses.

271

Making Imbibition Transfers to Paper.

21. Prepare paper in advance, or during dyeing of reliefs.

22. Transfer magenta dye.

23. Transfer blue-green dye.

24. Transfer yellow dye.

25. Dry print between blotters or on ferrotype tin.

FORMULAS

Dissolve all chemicals in the order given.

Developer (D-ll)

Avoirdupois Metric

Water (about 125°F.) (52° C.) 64 ounces 2.0 liters

Elon 60 grains 4.0 grams

Sodium Sulphite, Desiccated 10 ounces 300.0 grams

Hydroquirione 1 ounce 85 grains 36.0 grams

Sodium Carbonate, Desiccated 3 ounces 145 grains 100.0 grams

Potassium Bromide 290 grains 20.0 grams

Water to make 1 gallon 4.0 liters

Use without dilution.

Wash-Off Relief Bleaching Solution (R-10)

Stock Solution A

Avoirdupois Metric

Water 16 ounces 500.0 cc.

Ammonium Bichromate 290 grains 20.0 grams

Sulphuric Acid C.P 3Mz drams 14.0 cc.

Water to make 32 ounces 1.0 liter

Stock Solution B

Sodium Chloride (table salt) !*/£ ounces 45.0 grams

Water to make 32 ounces 1.0 liter

For use, take 1 part of A, 1 part of Bt and 10 parts of water.

Non-Hardening Fixing Bath (F-24)

Avoirdupois Metric

Water (about 125° F.) (52° C.) 16 ounces 500.0 cc.

Hypo 8 ounces 240.0 grams

Sodium Sulphite, Desiccated 145 grains 10.0 grams

Sodium Bisulphite 365 grains 25.0 grams

Water to make 32 ounces 1.0 liter

Permanganate Reducer (R-2)
Stock Solution A

Avoirdupois Metric

Water 32 ounces 1.0 liter

Potassium Permanganate 1% ounces 52.5 grams

Stock Solution B

Water 32 ounces 1.0 liter

Sulphuric Acid, C.P 1 fluid ounce 32.0 cc.

For use, take 1 part of stock solution A, 2 parts of stock solution B, and 64 parts of
water.

Important: When preparing stock solution B, always add the acid slowly to the water
while stirring the water rapidly. Never add the water to the acid, or the solution may
boil over and spatter on tha hands or face, causing serious burns,

Chromium Intensifier (IN-4)
Stock Solution

Avoirdupois Metric

Potassium Bichromate 3 ounces 90.0 grams

Hydrochloric Acid C.P 2 fluid ounces 64.0 cc.

Water to make 32 ounces 1.0 liter

272

Color Photography

For use, take 1 part of stock solution to 10 parts of water. Bleach thoroughly, then
wash for five minutes and redevelop fully (5 to 10 minutes) in artificial light or daylight
in any quick-act ins;, non-staining; developer containing the normal proportion of bi'omide,
such as Formula D-ll, diluted 1:3. Then wash thoroughly and dry. Greater intensification
can be obtained by repeating the process. The degree of intensification can be controlled
by varying the time of redevelopment.

Table of Dilutions of Acetic Acid

Concentra- Amount of Acetic Acid

tion in % Glacial Acetic Acid 28% Commercial Acetic Acid

1/10% 1 cc. diluted to 1 liter, or 3.6 cc. diluted to 1 liter, or

% fluid dram diluted to 1 fluid dram diluted to

32 ounces 32 ounces

Vz% 5 cc. diluted to 1 liter, or 18 cc. diluted to 1 liter, or

1*4 fluid drams diluted to 5 fluid drams diluted to

32 ounces 32 ounces

5% 50 cc. diluted to 1 liter, or 180 cc. diluted to 1 liter, or

13 fluid drams diluted to 5% fluid ounces diluted to

32 ounces 32 ounces

Aluminum Sulphate Solution for Mordanting Paper (M-l)

Avoirdupois Metric

(A) Aluminum Sulphate 6% ounces 200 grams

Water to make 32 ounces 1 liter

(B) Sodium Carbonate, ..Desiccated 1 ounce 145 grains 40 grams

Water to make 16 ounces 500 cc.

Add B slowly to A, stirring well during the addition. A white precipitate is at first
formed, but this dissolves upon stirring. If a trace should remain, it can be filtered out
with a rapid filter paper.

5% Sodium Acetate Solution

Dissolve Sodium Acetate. Anhydrous (E. K. Co.). 50 grams in 950 cc. water, or
dissolve Sodium Acetate, Anhydrous 1-2/3 ounces in 32 ounces of water.

1% Ammonia Solution

Add one part by volume of strong ammonia water to 100 parts of water.

Varnish Formula for Color-Film Transparencies (V-l)

Avoirdupois Metric

Gum Sandarac 365 grains 25 grams

N-Butyl Alcohol G*/> fluid ounces 200 cc.

Castor Oil 1% fluid drams 5 cc.

Oil of Lavender 14 fluid dram 1 cc.

Warm the gum sandarac and butyl alcohol together until the sandarac has been
entirely dissolved. (Caution: Butyl alcohol is inflammable, and should not be heated over an
open flame.) Then filter the solution through a fine, lintless cloth, add the castor oil
and the oil of lavender, mix thoroughly, and cool before using. The oil of lavender may
be omitted if the odor of the castor oil is not objectionable.

The Eastman Wash-Off Relief process is essentially very simple, once
understood and acquired. However detailed instructions and specific infor-
mation covering every step of the procedure are absolute prerequisites of
success in making color prints by this method. Accordingly the editors
feel that they are performing an important duty towards their readers in
briefly presenting the outline of the process. It is suggested that those
seriously interested address the Graphic Arts Department of the Eastman
Kodak Co., Rochester, New York, requesting latest issue of pamphlet
entitled "Color Printing with Eastman Wash-Off Relief Film". The Eastman
Wash-Off Relief Process is being constantly improved and latest informa-
tion should be secured from the Eastman Kodak Company.

273

PART II

LEICA IN SCIENCE AND EDUCATION

Face Lift Operation

Henry M. Lester

274

jfp. t ,,#«#** - << &*^&Mulll,>f'f>*»

'%^J* ' ' ^^^w*^

Pig. 182 Transportation

J. D. McCauley

THE LEICA IN VISUAL INSTRUCTION

ELLSWORTH C. DENT

CHAPTER 15

The onetime formal and rather bitter educational procedure of
the elementary and grammar school is giving way to the more
interesting and profitable method of encouraging the pupil in self-
activity. The pupil is placed in a situation where it is desirable to
make comparisons, secure information, and calculate solutions to
problems, thus developing a need for the use of letters, words,
figures, and other symbols of thought. The term, motivation, is used
to indicate this more effective training procedure.

Visual-sensory aids to instruction perform a definite function in
this procedure. A simple picture, carefully chosen, may bring a
series of voluntary oral discussions, written compositions and mathc-

275

matical calculations equivalent to many of the former fearful assign-
ments of themes and sums. Objects, themselves, may be used even
more effectively, but frequently it is impossible to have the real
objects available. Representations of those objects are next in value,
and the photograph is one of the most economical of all represen-
tations. The photograph, properly made or chosen, may be even
better than the object, especially for group instruction. Teachers
are realizing this and are beginning to develop series of pictures for
class instruction, very much as they might select reference books,
magazines and other aids.

Pupil-participation is exceedingly important as a motivating
agency. If the pupil, even the unruly one, can be made to feel that
his presence and cooperation are important in the scheme of things,

Pig. 183 This picture by Creigh-
ton Peet will gain the coopera-
tion and interest of young Child-
ren very Quickly and Stimulate
Conversation

life takes on a new meaning to him and education becomes something
more than an endurance contest. Pupils may collect specimens, clip
pictures from magazines and newspapers, build collections of hobbies,
and do many things which will serve a dual purpose: (1) develop
an intense working interest on the part- of the pupil, and (2) develop
a collection of materials which will be of inestimable value in teaching
present and future groups.

One prominent visual instruction director takes pictures of his
pupils in special situations. He secures a good picture of a pine-
apple field, for example. Next, he takes a picture of a member of the
class in which the picture of the pineapple field is to be used. By
clever photographic procedure, he combines the two to make a picture
of that pupil in a pineapple field. The combined picture is trans-
ferred to a lantern slide for projection. The pupil is instructed in
advance that he or she will be expected to tell, during the projection
of the picture, just how it seems to be in a pineapple field. In order

276

Fig. 184 Indian Children Fig. 185 Negro Children

Pictures to show how the children of different races look, live, and play

to do this satisfactorily, that pupil must find out as much as possible
about pineapples. Although photographic trickery is used to build
a false situation, that situation proves to be a great motivating in-
fluence and increases the interest of the entire group in that subject.
A similar procedure might be adapted to many situations.

Teachers are, properly, the most extensive travelers of any in
professional work. Travel does much to broaden the outlook and
increase the efficiency of the teacher. Some collect specimens of
various kinds to be used later in teaching. Others gather pictures,
pamphlets, curios, and the like, for the same purpose. But there is

Fig. 186 Harvesting in Siberia

Such a picture tells the story quicker :

Julien Bryan

md better than a thousand words

277

Fig. 187 Foxgloves

A series of pictures presenting complete information about these flowers,
in their natural environment, flower formation, malformation of one of the
blooms, and even a close-up cross section

an increasing- number. of those who are depending upon the camera

to record the experiences of travel which may aid in the classroom.

All forms of plant and animal life undergo important changes

during the summer months. Some forms complete their life cycles

278

Visual

during the period when pupils are on vacation from formal instruc-
tion. Things are happening which the child may not notice or may
not understand. The brilliant colors of midsummer are gone when
the importance and functions of color among living things are dis-
cussed in the classroom sometime between September and June. A
camera which will record the changes, including accurate reproduc-
tion of color, and will make them available for later use in the class-
room becomes one of the most valuable assistants any teacher could
choose. The camera which would be, satisfactory for this type of
photography might be used equally well to record any other things

Fig. 188 Threshing in New Mexico Willard D. Morgan

In the little town of Chimayo, north of Santa Fe, this interesting
threshing scene was photographed

of interest, including pictures of people, buildings, landmarks, points
of historical interest, rock formations, trees, animals, and the like.

Inasmuch as teachers are not endowed, normally, with unlimited
funds for such activities, it is necessary that photographic equipment
be selected which will accommodate almost any photographic task and
do it inexpensively. The Leiea camera is meeting such requirements
and is becoming increasingly popular among those who realize the
potential value of pictures in teaching.
Educational Use of Pictures

It seems proper, at this point in the discussion, to mention some
of the things to be observed in selecting or making pictures to be
used as visual aids. In the first place, the mere showing of a picture

279

to a pupil or to a class may be an absolute waste of time except as it
may inject variety into an otherwise dull classroom situation. An
intelligent teacher would not inject the study of Chaucer into a
class in the lower grades. Neither would that teacher assign prob-
lems in physics to a class in elementary mathematics. It is fully
as important to select the proper type of picture for use in any
given situation. The few simple suggestions noted below might well
be observed in outlining plans for the selection and use of pictures
in the classroom:

1. Pictures selected for educational use should be within the age, or grade-
level of the pupils with whom the pictures are to be used. (A picture of
the Parthenon would mean little to an elementary group and a picture of
Mary Jane's doll house would not be appreciated by pupils in the upper
grades.)

2. A few pictures which are pertinent to the subject under discussion would
be preferable to many. The use of too many pictures is more likely and
more harmful than the use of too few.

8. The pictures used should relate directly to the lesson or unit of instruc-
tion and should contain few or no irrelevant details. Anything which
may not so relate to the subject under discussion will have a tendency to
detract seriously.

4. Each picture should contain some object of familiar size. A person,
an article of clothing1, a pencil, or any other object commonly known to
pupils will aid in conveying a correct impression of the primary subject
of the picture.

5. Pictures should indicate action whenever action will aid in presenting a
natural situation. Animals moving about, children at play, farmers at
work in their fields, make excellent photographs and are vastly more
interesting than posed pictures.

6. Pictures must be mechanically correct and of sufficient size to be viewed
without eye strain. This applies particularly to projected pictures but
might be applied as appropriately to photographs and enlargements.

There are many sources from which organized picture units may be
secured. Some are for sale and some may be borrowed. The school which
is able to purchase an adequate supply of pictorial materials for use among
its teachers places those teachers in a fortunate situation. However, if it
should be possible for each school to purchase a liberal supply of available
pictures, there would still remain many occasions for the use of a camera
to record special activities and scenes of local importance or for special
application to teaching problems. Inasmuch as no school is able to pur-
chase all desirable material and many schools are able to purchase little
or none, a suitable camera becomes highly important to those teachers who
desire to -present instructional material in an interesting and effective
manner.

The Leica Camera

The cost of producing suitable pictures for school use has been
a hindrance to the wider use of appropriate illustrations. The avei-
age camera will produce a reasonably good picture under ordinary

280

Fig. 189 Dramatics Montage Designed by Barbara Morgan

From 1936 Pean, school annual, Phillips Exeter Academy, New Hampshire. The indi-
vidual shots are from the productions of "Macbeth and Androcles and the Lion" and were
photographed by students of Phillips Exeter Academy. *•

Teaching- the Deaf to Speak

Summar 50mm lens, f :2.2, 1/3, E. K. Super X film.

282

J. Winton Lemen

Visual

conditions but that picture is not ready for use in the classroom.
It is too small to be clear in all its details and it is not in proper
form for easy enlargement through projection. If enlarged as a
photograph, the cost is prohibitive, and it must be transferred to
glass or film for suitable projection. The latter procedure requires
special apparatus and materials, involving considerable expense.

The Leica camera, on the other hand, is capable of producing
film strips for projection at a ridiculously low figure. The teacher
who will follow a few simple directions can prepare such pictures
at a cost which will range from four to six cents per picture using
inexpensive apparatus for developing and printing. Furthermore,
this same camera may be used to copy large or small pictures for
similar projection. The Leica camera will photograph anything
from very small miscroscopic organisms to the largest things in the
known world. The chapters on Copying and the making of positives
give more complete information.

If it should seem desirable to use photographs of any convenient
size, or of various sizes, such enlargements may be made by using
enlarging apparatus which is both inexpensive and simple to operate.
Eefer to the chapter on Enlarging. The cost of such enlargements
will be very little more than the cost of the negative for the average
camera and the enlargements may be made to conform to any desired
size or type. The negatives may be filed in small space, cataloged,
and used for reference purposes as needed.

If it should be desirable to make and color lantern slides of any ^ or
all of the negatives, the procedure is more economical than the production
of slides by any other method, and the results are highly satisfactory- For
ordinary classroom purposes, the double-frame film slide produced by con-
tact printing of Leica negatives will be almost as satisfactory as the glass
slide and will be much less expensive.

Some teachers Jind that their regular duties require so much time
that it is impractical to use the small amount of time required to develop
and print or enlarge miniature pictures. In such cases the most logical
solution of the problem is to organize a small camera club of older stu-
dents who may be interested in photography. Such a club will serve many
purposes. It will train its members to apply leisure time in an interest-
ing and profitable activity. It will develop a greater interest in the pro-
duction and use of pictures throughout the school. It will" build a useful
and valuable collection of pictorial materials at low cost to the school.

Convenience is another attribute of the miniature camera which should
be given careful consideration. It may be carried in a handbag, in the
pocket, or suspended on a small strap. It is always ready for action and
may be adjusted to any special situation quickly. It is simple to operate
and all necessary adjustments are made in less time than is required to
mention it.

283

Fig. 190 Bark Splitting-
cm a Five Year old Peach
Tree from the low Tem-
peratures of 1929-30. Note
the Healing over of the
Exposed Area

Photo by M. J. Dorsey

The adaptability of the miniature camera is the greatest of all. The
various simple attachments which are available to adapt it to special situa-
tions cover every possible requirement. The wide range of available lenses
will accommodate anything anyone could photograph with any other camera
or group of cameras. In all this, the cost of operation is much less than
would be the cost of operating the ordinary pocket camera which uses
rolls of six to ten or twelve exposures.

The Miniature Camera in Special Subjects

Agriculture. One of the chief handicaps of the teacher of
agriculture in the average school is that the principal crops grow,
fertilize and mature during the months of the school vacation period.
The animal life of the farm has undergone important changes. There
are many printed reports of what has taken place and the teacher
may be able to describe the developments in an interesting manner.
However, a pictorial record of those changes could be made with the
Leica camera and used to enliven the classroom discussions of various
farm crops and animals.

The agriculture teacher who goes to fairs and other exhibitions
of the best in farm products might not be able to bring samples of

284

Visual

those products before his classes for study. It would be rather simple
to make a complete series of pictures of the most important ones.
The cost would be but a few cents per picture and the possibilities
would be unlimited. The convenience of small size makes it possible
to carry the camera constantly for the purpose of photographing
anything which might be of importance.

A further great advantage of the miniature camera is the ease
with which it may be used to copy charts, graphs, drawings, prints,
or other graphic materials for projection or reproduction. Frequent-
ly, valuable charts are accessible for study but may not be taken
from library or private collections. In practically all such case^,
permission to photograph those charts may be obtained. The photo-
graphs of the charts may be projected for study and are really more
useful than the original charts in some instances. The miniature
camera is ideal for such copying.

Biological Sciences. The possible uses of the Leica camera in
preparing materials for use in teaching the biological sciences are
unlimited. Photographs and photographic enlargements of speci-
mens of all sizes, types and colors may be photographed and pro-

Pig. 191 A Parent Bird and Family. "Photo by Charles A. Proctor

Fig. 192 (left) Cotton Blossom and Plant. This
Picture and the two Above give a Quick Impres-
sion of the Subject by Eliminating all Unessen-
tial Details

jected or reproduced accurately. A series of photographs showing-
successive changes in living forms may be made at little expense.
Flowers, birds, roots, leaves, seeds, insects, animals, and all usual
types of microscopic cross-sections, plants, and animalcules may be
photographed with ease and accuracy. Teachers who conduct re-
search during vacation periods or who may desire to produce special
pictures for class use will be unable to secure a substitute for the
miniature camera which, will fill the requirements at such low expense.
Languages. Objects are becoming increasingly important in the
building of a vocabulary. Projected pictures may be used in all
classes, from the lowest elementary grades through the foreign Ian-

Fig. 193 Peregrine Falcons Charles A. Proctor

A. mother and her youngster give the photographer a tough look

286

Visual

guage- groups in colleges and universities, for the purpose of fixing
new word symbols or clarifying the meaning of the old. The lan-
guage teacher who has long desired a collection of representative
pictures for use during the teaching of vocabulary may use the Leica
camera to copy such pictures from books, magazines, travel bulle-
tins, and the like. Furthermore, those who travel will be able to
prepare adequate collections of original photographs at low cost.

A projected picture in the classroom is one of the most potent
stimulators of oral expression and may be made the central topic
for a major part or all of a recitation period. All such expression
will but tend to develop greater facility in the use of words, regard-
less of the language employed.

Another profitable use of the Leica camera in language instruc-
tion would be for photographing and projecting charts of word

Fig. 194 The People of Tibet

Harrison For man

These pictures are full of details. Note man in the background holding- his
hands over his face... why? A market scene. . .ornaments. . .dress. . .super-
stitions

forms and endings, thus eliminating the tedious procedure of copying
such material on blackboards or on charts. With a little camera, a
little care, and a little energy, the energetic teacher will be able to
increase the effectiveness of instruction with a saving in time to all
concerned.

Geography. The myriad possible uses of the miniature camera
for the preparation of materials to be used in teaching geography

28v

Fig. 195 The Concrete Mixer W. H. Friedrich

An excellent action picture which shows the mixer in actual operation with humans to
give the scale and a more personal quality

stagger the imagination. Pictures of people at work and at play
in all corners of the earth may be photographed by those fortunate
enough to travel widely or may be copied from suitable photographs.
These, projected in the classroom, are second in value to travel in
giving true concepts of the way others live.

The same Leica camera may be used to copy detailed outline
maps which may, in turn, be projected against a white cardboard or
blackboard for study and for fixing locations. Pictures are exceed-
ingly valuable in the study of human relations and the miniature
camera offers the most economical means of providing those pictures.

Local geography is neglected frequently but could be utilized
to good advantage. Those features which are difficult to observe by
excursion or field trip may be photographed and brought into the
classroom. The fact that such pictures are of local situations will
tend to increase their value as related to the teaching problem.

History. Again, the teacher who travels may produce a series
of pictures which would be of inestimable value in the classroom.
It would not be necessary to travel widely. Local history forms an
important part of the instruction in all schools and could be made
a great motivating agency in both oral and written composition.
Pictures of landmarks of early development, homes of famous per-

288

Visual

sons, federal and state governmental buildings, and of any number
of other places could be obtained either by direct photography or by
copying from publications of all kinds.

The Leica camera is so inconspicuous and convenient to use that
many are able to collect excellent assortments of pictures of im-
portant figures in the events of the day. The possible use of such
a camera to produce pictures for use in connection with the study
of current events are many.

Industrial Arts. Here the Leica camera may be used to good
advantage for the preparation of either elementary or advanced
work. Certain master drawings might be photographed and pro-
jected on a screen for group study, a far more satisfactory method
than to make a drawing large enough for the class to study, and
incomparably better than passing an outline or a drawing from one
student to another. Furthermore, materials thus organized for pre-
sentation could be preserved in small space and brought out for
service as needed.

One instructor in engineering in a mid-western university uses
a miniature camera to copy drawings and outlines of special problems
and their solutions. Such problems are illustrated and discussed in
the professional magazines and the former method of this instructor
was to draw enlarged charts of ample size for the class to discuss

Fig. 196 How Are the Bones and Fragments of a Prehistoric Animal
Assembled and Mounted ? Photo by Dr. A. L. Lugn

289

Pig. 197 Stones For Grind-
ing Corn in an Arizona
Cliff City

Fig. 198 Betatakin Cliff
Dwelling in Arizona. A
City once Inhabited by
several Thousand Indians.
Photos by Willard D. Mor-
gan

as a group. Now, it is only necessary to photograph the page with
the little camera, make a print on film, and project that print to
any desired size. If charts seem desirable for use in the solution of
similar problems, they may be made quickly by tracing the projec-
tion on suitable paper. The process is simple, rapid, and inexpensive.
It would be almost as easy and but slightly more expensive to make
photographic enlargements for such members of the class as might
require them.

Architecture. This is the branch of engineering which is served best
by the miniature camera. Many interesting photographs of desirable
types of architecture may be made at little cost and studied at will. With
one camera loading of 36 pictures it is possible to photograph exterior, and
interior views of a building, and also make numerous close up detail views.
This strip may be reproduced on a filmslide strip for projection at a cost
varying from four to five cents per picture. The cost of making such
pictures with the miniature camera is so little that various angles of each
design may be recorded at less than the cost of a single picture of average
camera size. Small designs in professional publications may be copied and
enlarged to any desired size. So long as the resultant enlargements are

290

Visual

made for personal use and not offered for distribution, there is no infringe-
ment of copyrights or question of unprofessional ethics.

Physical Training. Many schools offer various forms of corrective
gymnastics. Students who seem to require correction of physical defects
or irregularities are photographed before the training is started. They are
photographed during the process, until correction ends. The miniature
camera, producing pictures with enlarging and projection possibilities,
becomes the first choice of the physical training supervisors who give this
record work serious thought.

The photographs of corrective changes are important but by no means
exhaust the possible adaptations of the miniature camera to corrective or
competitive athletics. The Leica camera is equipped with a lens and
shutter competent to photograph all types of action, stopping that action
at any point for careful study of form. In many instances, such stop-
motion pictures are as valuable to the coach or trainer as would be motion
pictures of the same athlete in action. These pictures may be used effec-
tively to point out both good and bad points in the form of the athlete.
The suggestions are vastly more clear to him than if made orally without
some form of supporting illustration.

Doctors and dentists who are charged with the responsibility of medi-
cal and dental inspection of school pupils are finding the miniature camera

Fig. 199 Dentition. Child 6 to 7 Years Old. Primary Teeth
Yielding to Pressure of Secondary Teeth. Photo by Henry M. Lester

to be of great value in photographing physical irregularities which need
correction, such as poor teeth, enlarged joints, improper muscular develop-
ment, eye defects, and the like. Peculiar situations may be photographed
for more detailed study through enlargement or projection. It is possible,
with this type of camera, to photograph the most minute structural details,
even those which are recorded through the lens of a microscope.

Physical Sciences. Many photographs maybe accumulated which will
illustrate, clearly, the application of the simple laws of science to the

291

Fig. 200 Hog - Nosed
Snake Photo by J. M.
Leonard

rather complex structure known as civilization and its environment. Pho-
tographs of geologic formations; the work of water, wind and temperature
as they change the surface of the earth; the effect of volcanic eruptions
and of glacial action; and of the application of physical laws to the mechan-
ical devices of industry, may be made quickly and cheaply.

Other Subjects. The suggestions made above are but a few of
the possible applications of the miniature camera to visual instruc-
tion. The enterprising teacher or visual instruction director will
find some use for such a camera in connection with the effective
teaching of almost every subject listed in the curriculum. One of
the great failings of textbooks for use in the elementary and inter-
mediate grades is that they contain illustrations covering situations
which are not within the understanding and personal experiences of
the pupils. It is not difficult to supplement the textbook illus-
trations with local pictures of similar situations, thus developing
a clear and logical understanding of the matters discussed in the text
and during the class period.

The application of the miniature camera to the problems of class-
room instruction by no means exhausts the possibilities of its use in
the school building or system. For example, one very successful
school administrator carries a minature camera wherever he goes
among the various buildings to observe the work in the classrooms
or to inspect the school plant. When he notices an unusually fine
type of project, he photographs it. If some student has completed
an outstanding piece of work, he makes a picture of it. If an altera-
tion or a repair is needed in a school building or among its equip-
ment, he may take several pictures of the situation. The resultant

292

Visual

pictures are prepared for projection before teachers' meetings, the
board of education, the building committee, or before any others who
may be interested in the work or welfare of the schools. These pic-
tures become a permanent record of progress, frequently quite valu-
able in clarifying misimpressions among those who are not thoroughly
informed concerning conditions.

The Leica camera is almost ideal for the production of pictures
of school activities to be used for all types of publicity. Although
the school annual is becoming less important to student life each
year, there are local and school papers and periodicals which make
good use of interesting pictures. Such pictures can be made with
this camera at a cost of a few cents each. It is almost certain that
many more good pictures will be available for such purposes than if
the cost should be several times that amount.

The school which may desire to make the most effective use of
pictures will find many uses for the miniature camera. Furthermore,
the cost of operation will be but a fraction of the cost of usual types
of pietiire making. The individual teacher or supervisor who may
be interested in building collections of illustrative materials for class-
room use will find the miniature camera to be an economical answer
to the problem of covering unlimited demands with a limited budget^

Fig. 201 Rock Structure, Segi Canyon, Arizona, Showing Horizontal
and Vertical Structure. Photo by W. D. Morgan

293

Dress Patterns in the Making Henry M. Lester

Drilling the Guide Perforations and Cutting a "Lay" of One Thousand
Patterns

Summar 50mm lens, 1/60 second at f :2.2, Super-X Film

Courtesy of Butterick Company

294

THE IN HISTORICAL RESEARCH

JAMES A. BARNES, Ph. D. CHAPTER 16

Modern scholarship demands of the research worker of today
impeccable evidence to substantiate his assertions. Such evidence can
very rarely be presented in the form of originals of historical mate-
rial. True copies are therefore required. These not only must be
good and accurate reproductions; they must be obtained speedily and
effectively. The Leica camera conveniently fulfills these require-
ments.

At one time the student spent the greater part of his day in
laboriously copying his finds or discoveries. Materials of the most
varied character — illegible letters, worn diaries, old faded news-
papers, statistical tables, and intricate election returns — may be
copied. These records can be secured photographically far more effi-
ciently and in incomparably shorter time. Subsequent ability to
enlarge to almost any size is an added advantage as it greatly con-
tributes to the legibility of such records.

There can never be a question concerning the accuracy of repro-
duction; not only the form of the original is retained in such a copy
but frequently even its spirit and intent.

The research worker, when he comes to writing, need not, as he
must when working from typed copies, wonder if the typist or the
original writer made the strike-over, the omission, the abbreviation,
the cancellation, the interpolation, or any of the peculiarities which
mark all human documents. The genuineness of signatures and hand-
writing and even the character of the paper used may be easily
authenticated. There can be no doubt as to whether a letter was
handwritten, typed, or printed; that a letter was dictated and
signed in his absence is easily discovered. Such apparently trivial
but sometimes important points as whether the address given on a
letter was merely a printed name or a part of the written manuscript
itself are readily established. Quotations in the final *copy for a book
may be checked against the original Document.

A very important asset in copying by camera is inclusiveness.
An entire manuscript or document can usually be recorded as

295

cheaply and as quickly as it can be extracted. Seemingly insignificant
sentences in a manuscript may take on, at a later date, a meaning
not discerned at the time of copying. The mere fact that a letter
contains no mention of a current event or existing condition may
later prove of great value if one can be certain that the omission
was committed by the writer and not the extractor. Adjacent par-
agraphs may give to a statement meanings or modifications not per-
ceived at the time the research worker copied the document. By
recording the entire original, the camera retains the proper setting
of desired extracts.

The camera not only provides accuracy, speed, and inclusiveness
in copy work; -it enlarges the field of research. No longer must the
scholar limit his labors to what seems at the moment important; as
already mentioned, he may copy somewhat lavishly without adding
perceptibly to the bulkiness of his material. Maps, charts, and graphs
may be readily copied in whole or in part. By use of the extension
tube the smallest section of a chart or graph may be lifted out
of its original setting and enlarged for particular study. The
cartoon, most pungent expression of contemporary opinion, may now

Fig. 203 Books, Manuscripts, Cartoons, and Similar Subjects can be
Copied for Historical Research. Photos by James A. Barnes

MAT ** *•»"» '*!

THE NATIONAL i

BIMETALLISM

ff EDITION. iW THOUSAND.

296

Historical Research

make up an important and significant part of the files of the research
worker who uses the camera. The writer's collection of several hun-
dred cartoons, gathered from every section of the country at small
reproduction expense, interpret the local attitude on economic and
financial questions in the period of the eighties and nineties more
poignantly, perhaps, than any other one possible type of source ma-
terial.

Obtaining Complete Historical Record Pictures

But maps, charts, graphs, and cartoons do not complete the list
of new sources made readily accessible. Highway signs, terrains,
badges, handbills, broadsides, uniforms, machinery and implements,
deserted villages, abandoned mining camps, relies, ancient, medieval,
and modern inscriptions, and even flora and fauna, are readily and
accurately recorded by Leica miniature photography. Whatever the
eye can perceive as source material, the camera can record and
preserve. My own files on the great depression of 1929 may in future
years prove richer because of their inclusion of photographs of silent
factories, of bread lines, of the unfortunates seeking warmth and a
place to rest in the St. Louis Public Library, of the bonus marchers,
of men and boys tramping the highways and riding the transconti-
nental freights looking for work, and of many other evidences of
economic turmoil. The New Deal may prove more interesting because
of a photographic record of the inauguration, of closed banks, of
farmers plowing under cotton, and of emergency workers on govern-
ment payrolls.

There are other advantages. The research worker often finds the
amount of time that he can spend at a given place limited. The
camera prolongs his stay in effect by enabling him to accomplish
more than he can by any other method of copying; it also permits
him to bring exact reproductions of the original documents to the
quiet of his own study for careful analysis and. interpretation. This
is particularly important where translation is necessary. The scholar
who works in European archives on a summer's journey has not the
time (and often not the money) to spend hours puzzling over a
manuscript the chief difficulty of which is translation, when he may
project the writing in an enlarged form on a wall or screen in his
own home.

A university friend whose time for traveling was extremely
limited recently photographed enough of the literature of the Penn-
sylvania Dutch in a few weeks to employ all his study hours for a
year. Transcription too sometimes presents problems. The writer

297

discovered a particularly valuable diary in Kansas; unfortunately,
it was written in a system of shorthand with which he was not
familiar. Its value was attested by the convenient fact that many
pages had been partially transcribed. The diary was photographed
quickly and cheaply and later consultations with expert stenographers
resulted in its complete transcription.
The Kesearch Equipment

The entire camera outfit for traveling research is little bulkier
than a typewriter. I recently completed a twelve-months research
trip through the West and the South in which I collected more than
twenty thousand copies of manuscripts. My equipment consisted of
a Leiea camera, Fuldy Copy Attachment, baseboard, upright and
sliding arms, two extension tubes, and two ordinary goose-neck lamps
fitted with one-hundred watt bulbs. It is well to carry also a develop-
ing tank and some standard prepared developer. Films may easily
be developed each night and carefully checked for omissions. This
cheeking is made reasonably simple in my own ease by the fact that
I keep a careful index of every photograph, recording the date, place,
person, subject, and collection or library from which the material is
obtained. The collection and library as well as an identifying num-
ber are easily photographed with each manuscript. Identification
and number may be on a simple typed slip or a regular holder
with movable letters and figures. The size of the original may be
shown by established measuring marks on the baseboard. Each roll of
film also is identified by a number, photographed at the beginning and
the end.

A scientific knowledge of photography is not necessary in order
to use the camera as a research instrument. Careful observation of
results and some idea of the fundamentals of lights and shadows are
helpful. The research worker is primarily interested in obtaining
the best possible photographs in the least possible time. He may be
compelled to compromise between quality and quantity. He cannot
spend too much time on artistry. The perfect negative, however, is
worthy of attempt because of the possibility of enlarging it for future
use as illustrative book material. For the beginning photographer
of ordinary manuscripts the two fundamental things to remember
are: first, keep lights as uniform as possible over the field to be
photographed; and second, be sure that the camera is in focus, The
£oose-neck desk lamps are conveniently carried, but care must be
exercised in placing them. Turn the shades so that the rays cross
over the manuscript. A magnifying glass is helpful in focusing, par-

298

Historical Research

ticularly on newspapers. The perfectly focused negative, regardless
of the size of the manuscript photographed, is easily read.

The length of exposure in copying varies with the intensity of
the light used, the size of the diaphragm opening, the color of the
paper which is being photographed, and the nature of the film em-
ployed. Practice alone can establish the best exposure for any par-
ticular equipment. The use of a dependable exposure meter is highly
recommended. The f :9 diaphragm opening has proved the best in
my own work. It is small enough to give clear-cut lines in the photo-
graph, and yet it permits enough light to ascertain whether the
manuscript is in proper condition, when iising the Fuldy attachment,
without opening the diaphragm with each exposure. Where single
sheets of paper of somewhat uniform size are being* photographed,
there is no need for repeated focusing.

The cheapest and perhaps best general film for ordinary repro-
duction seems to be the regular positive stock. This film with the
f :9 opening and two one-hundred-watt bulbs photographs black and
white papers at an exposure of about one second; yellowed newspapers
may run to three seconds. Allowances must be made for the difference
in intensity between direct and alternating current lights, and also
for extremely bright days. Filters are valuable, but longer exposures-
must be made when they are employed. Panchromatic film such as
Du Pont Micropan should be used and especial care taken in copying
graphs, charts, and cartoons which are intended for illustrations in
books.

FIRST BATTLE
OF MANASSAS

ItfENRY Hill LIES JUST TO THE SQUTH.J

[HERE THE CONFEDERATES REPULSED;
I THE BEPEATEfl ATTACKS OF THE UNION.
/ARMY UNDER McDOWELL, JULY 21,
(IB6L HE8E JACKSON WH THE NAME,

"STONEWALL^ AND FROM HEfiE 8E-

I (JAN MCDOWELL'S RETREAT THAT ENOEO

[AT*

Fig. 204 Highway Signs which Give Historical Information Should be
Photographed. Photos by W. D. Morgan and James A. Barnes

299

The most economical method of buying film is in bulk; the two hun-
dred-foot lengths have many advantages. The traveling research worker,
however, must learn to load both his cartridges and his developing tank in
darkness. Bathrooms and closets are most frequently pressed into service
as darkrooms, and one often finds that there is no place for attaching the
safety lamp. A little practice makes it possible to load in complete darkness
almost as quickly as with a lamp. An infallible test for determining the
emulsion side of the film is to touch it to the tongue because the tongue
sticks to the emulsion. Practice and observation, while they may not make
of the researcher an expert photographer, will soon lead to qualifications
sufficient for his work.

The student may use his material in two ways: either make enlarge-
ments on regular photographic paper, or else use a projector. For concen-
trated study enlargements on paper are preferred. Projection of the nega-
tive film itself of that material which is to be used only a few times is thor-
oughly satisfactory. The total cost per page when used in this manner is
only a fraction of a cent. If repeated projections are to be made, it is safest
to make them from positive prints. By carefully reading the special chap-
ters on developing, copying, making positives, and projecting, a thorough
understanding of this subject may be acquired.

The photographic method of research is certainly more econom-
ical and much more rapid than any other employed; it is also far
more accurate. On a research trip of more than fifteen thousand
miles the writer found no objections to the use of the camera. Own-
ers of manuscripts and documents are easily convinced that misinter-
pretation and misquotation are less likely to occur when the material
is photographed than when copied by hand or typewriter.

This Enlarging, Reading, and Pro-
jection Outfit, known as the Vokom,
can be used for Examining Nega-
tives or Positives. A small Mirror
is attached for throwing the Image
upon a Projection Screen. Note
Ventilating Ring around Lamp
Housing for use with Higher Power
Bulbs

300

AND

FRANCES W. BINKLEY CHAPTER 17

For the copying I do in iny study the camera is mounted on the
Leiea arm which slips over a 4-foot upright fastened to the table.
On the table beneath the camera concentric rectangles are drawn,
corresponding to the sizes given in the Leica tables for use with the
front lens. Along the top line of each rectangle there is written
the helical focus to be used for copying that size, the distance of
the camera from the object, and the amount of reduction. There
are five of these rectangles, from 8 x 12 to 13 x 19 inches. A plumb
bob dropped to the center serves as a check on the position of the
camera. Very satisfactory results may be obtained in focusing by
measurement with this arrangement, and it is more convenient than
the copy attachment excepting in copying material that varies greatly
in size.

If the camera is moved from its original position on the Sliding
Arm to the Sliding Focusing Copy Attachment, the lens position is
moved to one side and the field no longer corresponds to the rectangles
as drawn on the table. (In the Fuldy Copy Attachment that I use the
center is 2 inches to the left of the original center, when the Leica is
attached directly to the Sliding Arm.)

It is necessary to use a supplementary lens or an extension tube to
focus by measurement. If the various extension tubes are to be used
between the Leica and the lens the supplementary lenses are not
required. In this latter case use the tables given in the chapter on
copying. In case a definite checkup is required the single exposure
Leica is of value for securing exact focus for the various extension
tubes, as well as the different positions of the Leica lenses.

I have found that the f :3.5 lens plus the front lens No. 1 meets
all ordinary needs in copying. It is a good lens combination for
general work. However, where the type of material to be copied
varies from such small objects as postage stamps up to newspaper-size
pages, it would be convenient to have an additional lens or use the
ground glass copy attachment. The smaller apertures give better

301

definition, and it is a good plan to make stop f :12.5 or f :18 the usual
aperture in copying. It is possible, however, to make legible copies
with as wide an aperture as f :6.3 and this of course speeds up the
exposures. The character of the material to be copied must be taken
into account in judging the limits within which the aperture may be
opened. Since the smaller aperture means greater depth of focus, it is
not necessary to re-focus even in copying very thick volumes, when
the lens is stopped to f :18.

The Model F or G Leica (with focal plane shutter) make double
exposures impossible and are probably the most satisfactory models to
use in copying. Earlier models can be adapted by the use of a slow
exposure timer. If enough light is used to reduce exposures to one
or one-half second, there will very likely be considerable variation in
density unless the exposures are automatically timed.

The Model FF camera may be used in long copying jobs, because
of its greater capacity of film.

With the standard camera a half-dozen or more magazines may
be loaded in the morning and reloaded in the changing bag if they
are all exposed in the course of the day. (I keep a can in the
changing bag supplied with film cut in advance into 5 foot strips.)
This is very satisfactory for occasional copying, but in continuous
work loading the magazines and changing them in the camera takes

I O ,\ O U

PJ rorcdl afl<J arc to be fold by f. C«^ I

Prwwr to tlic wid Company i * * 5

Fig. 205 Title Page Showing-
the Lists of Deaths from the
London Plague of 1665. Photo
by F. G. Ludwig, Yale Library

302

Copying MSS

up a disproportionate amount of time. There are, however, compar-
able disadvantages with long rolls.

The Eastman or Du Pont process or positive safety films, bought
in 200 or 400 foot rolls, are satisfactory for copying any black and
white material. This safety film gives good contrast, and can be pro-
cessed in a dark room with yellow light, a considerable convenience for
the inexperienced worker. In copying colored material the panchro-
matic emulsions may be used. A document mimeographed in violet ink
came out very badly on the positive film, but gave an excellent copy
on Du Pont Micropan. Dr. Bendikson of the Huntington Library has
published a number of articles (Library Journal, Oct. 1, 1932, Sept.
.15, 1933, etc.) describing his methods and results in copying colored,
faded, blotted and charred documents.

In copying material printed on thin paper it is necessary to inter-
leave with white, to prevent the page underneath from showing
through. Where the ink on one side of the page shows through on
the reverse side I interleave with black, as this reduces the contrast
and may eliminate the show-through on the negative.

Spring clips and rubber band's may be used to hold the paper flat in
copying, or a piece of plate glass may be placed over the object. Glass is
troublesome to use as it must be watched carefully for reflection and flare.
In a library where the equipment is available the camera may be mounted
on the photostat machine, so that the photostat copy holder and illumination
can be utilized.

Two desk lamps with 100-watt bulbs give adequate illumination for
copying, with a slow exposure. They may be placed one on each side of the
object, the lamp placed 18 inches above the outer edge. This is not a perfect
lighting system, as there is a variation with the size of the page copied.
This variation however does not visibly affect the density of the negative
(or length of exposure) in copying up to folio size pages. When newspaper-
size pages are copied it becomes necessary to use two lights at each side.
Care must be taken to avoid a flare spot on the curve of the page in copying
bound material. When the paper has a glossy finish, tissue paper hung
over the lights will increase diffusion.

With two 100-watt lights, placed as described, and an aperture of f :18
the exposure will be between 4 and 6 seconds on process film. Two seconds
will result in a negative too light to be read easily in the projector, 8 sec-
onds will be too dense. By substituting Photofloods for the 100-watt lamps,
the exposure can be reduced to one second, and by enlarging the aperture it
is possible to copy with an exposure of l/20th second. There is no appre-
ciable decrease in contrast with the use of photofloods, or with the use of
Cooper Hewitt lights.

Since the time necessary to turn pages and arrange the document is
always longer than the actual exposure, there is usually no advantage to
be gained in working close to the limit of good definition with a wide
aperture.

303

The small tank may be used for occasional films, but for developing a
number of strips, the most satisfactory method seems to be simply to stand
the film on edge in a deep tray, drawing it out to prevent adhesion in curling
Several strips may be handled' at once in this manner and with an assistant
present to hand the strips a large quantity of film may be developed
within a short time, without any equipment except the tray. Where ex-
posures are as standardized as they are in copying there is no great need
for developing by inspection. In copying printed and written materials, the
beginner must not forget that he is aiming at contrast rather than the
soft tones sought in pictorial work. Emphasis in developing should be on
securing contrast. There is little difficulty in obtaining adequately fine
grain results with the process films.

Extreme care is necessary to avoid scratches and spots since they may
obliterate essential words or letters of the document copied. The film should
be touched only on the edge, and should not be allowed to drag across the
side or bottom of a tray, where sediment may scratch it. Chamois used in
wiping the film before drying should be free from grit.

Where negatives are valuable it is a good plan to give them a
second bath in fresh hypo and a double period of washing to insure
permanence.

As soon as they are well dried the film strips should be rounded
at the ends and placed in the containers. It is said to be advisable to
roll the film with the emulsion side out.

The need for cleanliness in the dark room is frequently men-
tioned and should be called most emphatically to the attention of those
whose darkroom, as is often the case with amateurs, is in the basement
or the attic, where there is apt to be a good deal of dust. Film that
is allowed to become dusty soon becomes scratched. It should not
be dried in a room where spilled hypo has dried and crystallized.
The amateur engaged in copying will produce a much greater bulk
of film negatives than would likely be produced in pictorial work,
and it is therefore necessary to care for a considerable number of
strips if processing is done at home.

Making and Using Film Copies . . .
The Clerical Side

A system of filing and identifying negatives is an important
factor in putting a collection of film copies to the best account. Most
of us follow the line of least resistance and if there is a good deal
of bother about unwinding film and searching for the piece wanted
we are inclined to neglect the film copies, no matter how excellent
the photography may have been. The following plan fits my own
needs and might be adapted to the use of others.

The film strips are numbered and filed under headings that
parallel those in a general file of notes and documentary material.

304

Copying MSS

Crumbling of Newspaper Files
Declared Loss to Historians

"By The Associated Press.

. MINNEAPOLIS, Dec, 28.— "Tons
of history" are being swept tip
daily from the floors of American
libraries because of the absence of
art economical preservative to pre-
vent ruin of n^wspap^r files,, the
American Council of Learned So-
cieties was told here today.

' Wood pulp paper, with which
most of the presses are fed, serves
the historian badly because it
cracks, tears and crumbles, threat-
ening destruction of a primary
source of material for future in-
terpreters of modern life, Dr, Solon
JV Buck of the University of Pitta-
burgh said,

He suggested that cameras capa-
ble of reducing facsimiles of news-
paper pages to small size requiring
little space in archives might solve
the .problem in part but that a low-
cost* adequate preservation which
would. insure the safety of original
files was the greatest need.

Fig. 206 Newspaper Clipping
Warns Against the Loss of
Valuable Records

Fig. 207 Cover of an Early Medical
Book Copied for Later Study

A record of the material copied is photographed in each case and
becomes part of the negative, serving as a label.

The first exposure on each strip of film copies a large number
that can be read on the negative without a lens, and a good deal of
eye strain is avoided in identifying film strips by this large number
at one end. The numbered series serves as a check against the loss
of film in process or in use.

The second exposure copies a label, which contains the following
information :

a. title of document

b. filing designation

c. photographic conditions

d. number of pages copied

It is not necessary to use an entire frame for this label, as it
may be placed alongside a title page and photographed in that posi-
tion. After the entire strip of film has been exposed, the number of
pages copied may be noted on the original label, and if the document

305

has not been completed the label may be carried forward to the next
film strip. The original label is eventually filed in the general file,
with other notes, and serves as a cross reference to the film. In
special cases, as in copying a series of documents, it is convenient
to keep a list of the contents of the film strips, taken from the labels
before they are filed.

The entry on photographic conditions may be referred to in comparing
the results of various methods of copying, and also in planning retakes
where the copying has not been successful. If a large amount of material
has been copied in the course of travel, a note on the label of the condition
of the document, color of ink and paper, and the exposure given, will explain
the results in the case of a poor negative and may be taken into account in
ordering retakes. If missing pages or other variations in the document are
noted on the label it will save turning again to the original in checking-
over the film negatives.

It is a good plan to number the exposures or frames in copying. Small
cardboard squares which stay in place when dropped at the corner of the
page are desirable (mine are hat check numbers). These frame numbers
are used in collating enlargements or in giving orders for enlargements to
be selected from a film strip. A running title, typed on a narrow piece of
heavy paper and placed at the bottom of each page, is also useful in identi-
fying enlargements and in identifying pages as they are read in the pro-
jector.

To add the frame number and running title, interleave pages to prevent
show-through, and attach spring clips to hold the pages flat, — all occupies
about twice as much time as the actual exposure in copying. In my experi-
ence, however, the time is saved twice over in the future use of the negatives.
To assort the enlargements from a number of film strips, if they are not
numbered, will sometimes take as much time as the photographic process
itself. On one occasion, before I adopted the numbering system, I had
copied several slightly varying drafts of a single document, had 75 enlarge-
ments made, and found it was necessary to compare each enlargement with
the original in order to be sure the pages were arranged in correct sequence.
It took as much time as a jig saw puzzle.

An advantage of the film copy method is that proofreading is
riot required. It is necessary, however, to look over the film, with a
lens, first to see that it is satisfactory from the photographic poini
of view, and then to discover if what we might call clerical errors
have occurred.

Copying Mistakes and Their Remedy

Faults in photography most likely to be encountered are, first,
those in exposing, such as errors in focusing, the object not being in
the center of the field, over or under exposure, spots caused by im-
proper illumination or by reflection from bright objects near the page
copied, and the like. Second are the accidents in processing, such as
scratches, pin holes and water spots, and over or under developing.

306

Copying MSS

The most likely clerical errors are mislabeling of documents, or
skipping pages. The following device serves as a check on missing
pages, so that it is not ordinarily necessary to check them on the
finished negative.

I connt thirty pages in the document and place a marker at the
end. If the camera counter, the frame numbers, and the marker in
the document coincide at the end of the strip, it is reasonably certain
that no pages were omitted. If an error has been made the best way
to correct it usually is to retake the whole strip. This avoids isolated
pages, taken at a later time, which must be spliced on to the film strip.

Film Storage

I keep the Leica film strips in small tins, labeled on the top. These can
be arranged in rows in a shallow drawer and treated, so far as filing is
concerned, as if they were folders in an ordinary vertical file. The label
on the tin corresponds to the file designation photographed on the film and
also, of course, to the headings in my general file.

Where there are a number of short takes on a strip, I cut them apart,
disregarding the strip number, and file the short slides with other material
in the general file. Paper folded and pasted on the back of a folder forms
pockets to hold the film.

The best advice on storage that I have been able to obtain indi-
cates that proper processing is the prime condition of film per-
manence. There is apparently no great danger of loss if the film is
kept in a reasonably cool place. Since almost all my film is on the
acetate base there is no more fire danger involved in keeping It thau
in keeping papers of any sort.

Reading the Negatives

After the copies are made and filed in some safe and easily accessible
manner, the problems involved in using them are relatively simple. The
film may be used in short or long strips, on reels, or the frames may be cut
apart and mounted individually in cards, to be used as slides. When suit-
able reading devices are available the film may be projected to a convenient
size and read at close range in a light room, so that a typewriter may be
used in making notes. If the projector used will not allow a light at the
desk, it is still possible to record notes on a dictaphone as the film is
studied.

When enlargements are desired, they may be greatly reduced or made
as large as required. Copies of newspaper clippings, for example, may be
enlarged to twice the original size, or on the other hand a series of letters
may be reproduced to fit a 3 x 5 card file. Such papers as Photostat R,
Insurance Bromide, and Haloid Record are satisfactory for enlargements.

If a few frames are to be selected for enlargement from a long strip
of film, the enlargements may be indicated by the frame number or by
short pieces of string tied into the perforations.

In planning for enlargements in large quantity, it must be taken into
account that they add a large sum to the very low cost of the film copy, as

307

well as increasing the bulk of material to be stored. To the cost of making
the enlargements should also be added a charge for clerical work in assort-
ing and checking over the finished copies. It may also be decided to mount
the enlargements, to get away from the tendency of the paper to curl, and
this adds another charge. If a suitable projector is available the beginner
in the field of film copy ought by all means to give a fair trial to reading
the film by projection before deciding out of hand that all his film copies
must be enlarged.

Tiger Beetle

J. M. Leonard

308

THE MINIATURE CAMERA FOR

MINIATURE MONSTERS

J. M. LEONARD

CHAPTER 18

The photographer who is weary of portraits and pictorials or
who is bored by the discussions of purist versus creative may take
new hope. If he wishes to combine amusement and education with
a host of interesting photographic problems, he should explore the
world of miniature monsters which awaits him in his own backyard.
He will find a life as fascinating and as bizarre as any that ever
roamed the hot sands and the reeking swamps of prehistoric times.

Such an exploration, through the eye of the camera, will reveal
creatures clothed in bone, in feathers, and in hair; creatures with
from two to eight eyes, and from one to nearly thirty thousand lenses
or facets to each eye; creatures so weird in appearance that they seem
to belong to another age. These are the insects and the spiders.
Their variety of form is boundless and in brilliancy of color they
equal if not surpass the most gorgeous flowers. Their habits and
their social conduct are of such absorbing interest that the insect
photographer need not feel surprised should he suddenly find himself
more interested in studying the actions of the insects than in pho-
tographing them.

309

Entomologists estimate that there are a half million or more
known species of insects. They constitute by far the largest group
of Hying creatures and greatly exceed the combined total of all others
on the earth, in the air, and under the water. Doctor Frank E.
Lutz of the American Museum of Natural History states that there
are approximately fifteen thousand species of insects to be found with-
in fifty miles of New York City, and nearly eleven thousand species
within the state of New Jersey, and these, bear in mind, are species
and not individuals. The photographer who takes up this branch of
work will never lack subjects. Also he will have a year around hobby,
for the insects may be photographed alive in the field or may be
mounted and saved for the long winter evenings.

Catching the Insects

Although insects are so numerous and so widely distributed a
few hints as to where to look and what to look for might be helpful.
The collector doubtless needs no suggestions as to where to find such
household insects as the roach, silver fish, clothes moth, house fly and
mosquito. These, however, constitute a very small percentage of the
thousands of varieties which lie beyond the screens and the front
door.

Pig. 208 Head of Wolf Spider Pig. 209 Head of Jumping Spider
Note How Eye Arrangement Differs

310

Miniature Monsters

2L*

Fig. 210 The Northern Centipede which Lives in Houses

While many insects are much in evidence some of the most in-
teresting ones prefer seclusion and their society must be sought.
Turning over an old board or a rock in a field may admit one to the
private lives of a few crickets, a family of sow bugs, or a miscellane-
ous collection of beetles. Other insects will be found under bark, in
rotten wood, in flowers, among the roots of plants, and in fact prac-
tically everywhere that the careful collector cares to look. The chief
requisites of a collector are active curiosity, quick fingers, and nimble
legs. For the capture of moths, butterflies, dragon flies, or other
flying insects a net is essential. This may be purchased for a rea-
sonable price from any dealer in entomological equipment.

While all insects are interesting photographically, there are a
few of the common ones which, because of certain outstanding points
of interest, should appeal to the beginner in insect photography.
The spiders — which by the way are not insects but are of the class
Araclmida, order Araneida — are interesting because of their ferocious
appearance and the number and arrangement of their eyes (figs. 208
and 209). The normal number of eyes is eight and all of the eyes are
simple : in none of them is the outer layer divided into facets as in the
compound eyes of insects. The normal arrangement is regarded as
two rows, each containing four eyes, but they may be found in three
and even four rows. Grasshoppers are interesting because of their
smug expressions (fig. 211). Scutigera Forceps, the northern centi-
pede which lives in. houses, appears like a "bleached carcass on the
desert when photographed on sand against a black background (fig.

311

Fig. 211 Grasshopper

Elmar 135mm lens, S. F.
Attachment, 60mm ext.
tube, 36 seconds, at f:18,
DuPont Superior Film

210. The larvae of many of the large moths such as Cecropia, Prom-
ethia, and Cynthia look like prehistoric dragons in the photographic
enlargements. The points of interest are endless but the experimenter
will soon find his own favorites.
The Camera Equipment

The camera used in photographing insects must fulfill several
important requirements if the best results are to be secured. Ground
glass focusing is essential because of the very small depth of focus
which is available when the object to be photographed is only an inch
or two from the lens. The equipment selected should be such that
the distance between the lens and the film may be varied sufficiently
to produce either photographic reduction or enlargement of several
diameters. The range in the size of insects is such that a fixed
amount of bellows extension will not serve for both the large and
the small ones. The image of a praying mantid would have to be
considerably reduced before it could be recorded on a 35mm film,
whereas a mosquito or a fly would need a corresponding amount of
enlargement to bring out any detail.

The Leica camera, which is used hy the writer, fulfills all of the
essential requirements. The sliding focusing copy attachment provides
ground glass focusing, and the lens extension tubes which are used with it
permit a wide range of photographic reduction and enlargement, particu-
larly when used with lenses of different focal lengths. As an added ad-
vantage the copying- attachment and camera may be mounted on a tripod
and used in the field for photographing live insects. The question of which
model of the Leica to use is significant only in one respect. Any model is
satisfactory but the Model F has the outstanding advantage of including
speeds between 1 and 1/20 second, and it is in this range that many of the
insect exposures will be made.

The accessory equipment for this branch of work will vary with the
ideas of the individual and with the state of his pocket-book. A fairly
comprehensive list is as follows:

312

Miniature Monsters

Sliding1 Focusing Copy Attachment and Magnifier
30mm, 60mm and 90mm Extension Tubes

Elmar 35mm lens Elmar or Summar 50mm lens

Lens Shade Wire Cable Release

Ball Jointed Tripod Head "Triax" Tripod

For field work the 50mm lens and the 30mm tube generally will be
sufficient. This combination in connection with the Copy Attachment will
produce a .82x magnification of the image which is about all that can
be tolerated when working with a live insect of average size. If greater
magnification is used it will be difficult to obtain critical focusing because
of the reduced depth of focus combined with the need for fast work when
photographing a live insect. The additional tubes and the 35mm lens will
be found useful for higher magnifications when the work is done indoors
under controlled conditions.

Photographing in the Field

Photographing the insects in their natural haunts will provide
the occasion for many a long and interesting walk. The woods, the
fields, and the shores of ponds and streams are teeming with life. The
close observer will find ceaseless activity and industry to an extent
unrivalled among living things. He will find every trait and char-
acteristic that can be found in human beings and many others besides.

For field work, the equipment should include the sliding focus-
ing copy attachment and magnifier, a 30mm tube, lens shade, tripod
with ball jointed head, and wire cable release. In addition, a can
of ether or carbon tetrachloride, a small glass jar and a medicine
dropper will be found useful.

A little experience in trying to photograph a live active insect
will soon show the difficulty of doing so. Some insects are easily
frightened and others appear to have a constant urge to go some-
where. Usually by the time the camera is set in place and the some-
what critical focusing has been done, the insect has succumbed to this
urge and is nowhere to be seen. The job will be made much easier
and the chances of a successful picture increased if the insect is
placed under better control.

The following method has been used with good results :

1. Select a twig, shrub, rock or any other place where you would
like to have the insect resting when it is photographed.

2. Focus the camera on the particular spot selected.

3. Next catch the insect and place it in the jar with a few drops of
ether or carbon tetrachloride. It should be carefully watched and
should be removed from the jar as soon as it appears stupefied.

4. Place it in the spot previously focused on, arrange its legs in a
natural position, quickly check the focus and take the picture.

313

If it has been etherized just the right amount It will be able to cling

to the twig or leaf but will not be able to crawl or fly away for a minute

or so.

Too much ether will kill it, and too little may enable it to leave before

the picture is taken.

The insect may be mounted in the field if desired and thus kept
under more complete control. About twenty years ago Dr. David
Pairchild of Washington, D. 0., made a number of very interesting
insect photographs which were published in the National Geographic
Magazine and later in book form as "The Book of Monsters". Dr.
Fairehild describes Ms method of mounting as follows :

"Cover the top of a small block of wood with a thin, even coating of
paraffin or ordinary candle wax by letting the drippings of the candle fall
upon it. Pick a large leaf and turn its upper surface down upon the wax,
before it cools, and let it stick there; this will give a natural looking ground
for the insect to stand upon. Hold the insect over the block of wood and
arrange the legs in as natural a position as you can with a long needle or
fine dental tool. Then fasten each foot in place by heating the needle in the
candle flame and pricking a hole in the leaf just under each foot so that the
wax will come up through the leaf and hold it fast." The insect^ is anes-
thetized just before the mounting operation is undertaken, and is photo-
graphed immediately after it is mounted.

There are times when it pays to proceed with caution and to
observe closely what the insect is doing instead of immediately cap-
turing and etherizing it. An interesting series of pictures may be
the reward of restraint and patience. The insect may be engaged
in an operation which is seldom noticed and less frequently photo-
graphed. Careful scrutiny may show a cricket laying its egg through
a long tube which has been thrust into the earth, a jumping spider
dancing before its mate or a praying mantis depositing its egg mass
as shown in figure 213.

The mantis series resulted from wondering why this insect was
lightly tapping the stick with the end of her body. It seemed to be
an unusual procedure and was one which the observer had not seen
before. After watching this seemingly futile performance for twenty
minutes the observer was rewarded. The mantis began to exude a
frothy substance from her body and carefully worked this into place
on the stick. As it was apparent that this was the beginning of the
egg mass the Leica was hastily set up and a picture was snapped.
Pictures followed at ten minute intervals for the two hours and
twenty minutes she required to complete the operation.
Selecting the Correct Photographing Angle

In insect photography, as in any other kind, the position of the
camera in relation to the object being photographed is an important

314

Miniature Monsters

factor in determining' whether or not the picture will be interesting.
A photograph of a man or a horse taken from an elevation with the
camera pointing directly downward would not be particularly pleas-
ing and would give little idea of what the subject really looked like.
Following this line of reasoning best results will be obtained if the
camera is in the same plane as the insect, or in other words, at insect
level, although this rule may be varied by angle shots from slightly
above or below the subject. This point is illustrated in figure 212
which shows two moths, one photographed from above and the other
from the side.

It is for the reasons given that the "Triax" tripod is suggested for
field work. It is one of the few that is so constructed that the legs when
spread out so that they are in one plane, cannot be raised above that plane.
When the tripod is placed on the ground with the legs spread in this manner
the camera will be only a few inches above the ground and will be rig-idly
supported.

The proper exposure time can best be determined by means of an ex-
posure meter, bearing in mind that a correction factor must be applied if
the extension tube is used. Using the 30 mm. tube and the 50 mm. lens set
at infinity with the diaphragm at f :6.3 the exposure as determined by the
meter should be multiplied by 2.2. It should be remembered that when
an extension tube is used between the lens and the camera the f values of
the diaphragm do not mean the same as when the lens is used without the
tube. Moving the lens away from the film increases the size of the image
at the plane of the film and therefore a given amount of light coming
through the diaphragm aperture will be spread more thinly over the image
than would be the case with the lens in its normal position in the camera.
This is equivalent to reducing the f value and proportionately longer ex-
posures will be required.

Field trips in search of insects will disclose other interesting
subjects for the camera. The hog-nosed snake, the neighbor's cat

Fig. 212 Cecropia Moth
Luna Moth (right)

315

Pig. 213 A Praying Mantid
Depositing its Egg Mass

316

Miniature Monsters

These Pictures were taken at ten-mixmte in-
tervals during the two hours and twenty
minutes required to complete the egrg
mass

317

and the lizard (fig. 214) are among the many trophies of such
rambles.

Bringing Home the Catch

If the insects are to be brought home to be mounted and photo-
graphed at leisure, instead of being photographed in the field, small
straight sided bottles having large mouths and screw caps will be
found convenient for transporting them. A word of caution, how-
ever, about properly segregating the occupants of the bottle. The
writer, on one of his collecting trips, found some magnificent speci-
mens of huge black and red ants. He captured a half dozen of the
finest looking ones and placed them in a small cardboard box. He
carefully brought the box home and opened it to find a grand
collection of spare parts — legs, heads and bodies scattered about.
In the midst of the destruction was the victor — minus all six legs-
still waving avid mandibles in search of more victims. A safe rule
is to have a separate container for -each insect.

Moths and butterflies should be killed as soon as they are cap-
tured. This may be done by carefully but firmly pinching the thorax
between the thumb and finger. If they are alive when placed in the
container they will thrash about and injure their delicate wings,

Mounting the Insects

Insects which are to be photographed at leisure must be per-
manently mounted. This is a difficult job and, if naturalness is to
be achieved, calls for steady hands and endless patience. There
probably are many ways of mounting and the experimenter may wish
to develop his own.

A method which was adopted by the
writer after many experiments is as
follows :

Take a piece of cardboard measuring
about 2x3 inches for the smaller insects
and proportionately larger for those of
greater size. Cement to this a piece of
Dennis on's gummed cloth mending tape
with the gummed side up. Place the ether-
ized insect on this and putting each leg in
turn in the proper position, moisten the
gum around the foot with a small pointed
stick which has been dipped in water. The
events leading up to and following this op-
eration are as important as the mounting
operation itself. The live insect is carefully
studied until all of the details of one pose
are firmly pictured in the mind. This in-
Pig. 214 Gila Monster eludes the position of the antennae and of

318

Miniature Monsters

i '* ' *" "i^tewAji* j

Fig. 215 A Praying Mantid — Showing one Method of Mounting

each of the six legs, the angle of the head and of the body, and the distance
between the under side of the body and the mounting surface. The insect
is then etherized. This may be done by inverting a water glass over it and
placing a few drops of ether under the edge of the glass with a medicine
dropper. Experience will show the proper amount, which varies greatly
according to the kind of insect. A few drops suffice for a fly while some
beetles and spiders literally must be bathed in it. Care must be taken to
remove the insect after it is properly anesthetized. Too much ether will
kill it, and the way the contracting muscles of a dying- beetle will pull its
six legs into a tangle would discourage the most patient experimenter.
Place the insect quickly on the gummed tape and fasten each foot in the
position it assumed when alive. After this job is about half done the
chances are that it suddenly will come to life and pull its feet free so that
the whole operation will have to be repeated.

When all legs are in place the insect is blocked up to the proper height
by inserting under it small rolls of tinfoil or bits of cardboard. The head
is held at a natural angle in a similar way or by letting it drop into the
crotch formed by two pins which are stuck into the cardboard in such a way
that they cross just under the head. The antenna may be held sloping
upward to the front by a piece of cardboard so folded that one part of it
rests flat on the mount forming a base for the other part which extends
upward at the desired antenna angle. The antennae are carefully laid on
the sloping piece. Antennae which are carried in a horizontal position may
be held in place by a small block of tinfoil placed under them. Legs which
tend to buckle in the wrong direction are braced by pins stuck into the

319

Fig. 216 The praying
Mantid shown in Fig. 215
after the Mounting Pins,
Blocks, etc., have been Re-
moved

cardboard mount. Ordinary pins may be used but those are not as satis-
factory as the pins used by entomologists for mounting insects. This pin
is about 1V2 inches long and has a very small head and a sharp point.
After the insect is finally mounted and is blocked in a lifelike position it
should be killed. One of the most satisfactory ways of doing this is by
inverting a large mouthed cyanide bottle over the insect. The cyanide
fumes do their work in a very few minutes. The insect is carefully put
aside to dry and in four or five days the pins and blocking may be removed.
The insect will remain permanently in the position in which it was mounted.
Figure 215 shows a praying mantis which was mounted in a fighting pose by
the method just described. Figure 216 shows the same insect as finally
photographed.

The supplies and implements for mounting are few and simple. They
are: a can of ether, a medicine dropper, some pieces of cardboard, a small
sheet of tin or lead foil, a roll of gummed cloth mending tape, a tube of
cement, one or two long flexible tweezers, some pins, and a few slender
pieces of wood with needles stuck in their ends. The needles are used for
arranging the insect's legs and antennae. One of them may be made more
useful by heating the needle point and bending it into a very short hook.
One more accessory which is almost a necessity is a binocular loupe magni-
fier such as is used by oculists. Lacking this a reading glass may be used
but it should be mounted on a support so that both hands are left free to
work on the insect.

The question has been asked many times as to how insects
should be preserved to prevent decomposition. The answer is that
preserving is not necessary for the reason that the insect wears its
skeleton on the outside. The outer part of the insect's body is com-
posed of a substance known as chitin. This is an organic chemical
compound and the parts of an insect's skin which contain it are
hard, tough and lasting. Spiders, however, require special treat-
ment as otherwise the body will gradually shrink and collapse until
it is flat and unnatural in appearance. Before mounting a spider
the under side of its abdomen should be slit open and it should be
thoroughly cleaned out. It should then be stuffed with cotton until
it is filled out to natural size and appearance.

320

Miniature Monsters

To prepare the mounted insect for photographing* a thin layer
of fine sand may be sprinkled on the cardboard mount to produce a
natural looking foreground. A piece of cloth or cardboard may be
placed a few inches beyond the insect for a background. This may
be white, black, or some shade of gray depending upon the color of
the insect and the photographic effect desired. For a dead black
background a piece of black velvet is excellent.

Lighting

Lighting a subject as small as an ant or a fly in such a way as
to bring out the desired contrasts is difficult and requires much
experimenting. Almost any source of illumination can be used, but
the results obtained will be somewhat dependent upon the amount
of control that can be exercised in the application of the light. The
lighting originally used by the writer consisted of three 100-watt
Mazdas in goose neck desk lamps. While fairly satisfactory results
were obtained with this lighting arrangement it was not all that
could be desired. The size of the light source was so large com-
pared to the subject being photographed that it was difficult to
produce the desired effects. Photoflood lamps may be used if it is
desired to materially shorten the exposure time, but these too have
the disadvantage of being much larger than the subject.

The most satisfactory lamps so far used were improvised from old
style De Vry still projectors. This so called projector really consists of only
a lamp housing with its support and a very good condenser system. Pro-
jection originally was accomplished by clipping a De Vry camera in front
of the condenser and using the camera lens as the projections lens. The
camera however is not necessary in constructing the insect spot lights. The
first steps in adapting the projector are to remove the lamp housing from its
support, discard the support and the transformer which it contains, and
substitute a double contact bayonet socket for the single contact socket.
The double contact socket is standard and may be obtained in any automo-
bile supply store. A 50 or 100 watt 115 volt projection bulb will fit this
socket and is the right size for the lamp housing. The housing should then be
mounted so that it may be moved up and down or may be tilted. This
requires only a little ingenuity and in figure 217 it is shown in use. It con-
sists of a lead-filled lamp base, a rod with sliding- clamp which ordinarily is
used to adjust casement windows, and a brass coat hanger for adjusting the
position of the lamp when the housing becomes too hot to touch. A piece of
ground glass clamped in front of the condenser lens to diffuse the light com-
pletes the outfit. This lamp produces a brilliant concentrated spot of light %
inches in diameter at about 2% inches in front of the condenser lens and a
well diffused light at a distance of eight or more inches. The light has a
value of 1500 to 1800 candles per square foot in the % inch spot and about
600 candles at the 8 inch distance.

In arranging the lighting in preparation for the exposure a good
general rule is to place lights on both sides of the subject with a

321

Fig. 217 Close-
up View of Pho-
tographic Equip-
ment Showing1 Po-
sition and Con-
struction of Spot
Light and Ar-
rangement of In-
sect and Lens

third light above and to the front of the insect. In order to avoid
flat lighting the lamps should not be equidistant from the subject,
but should be so placed that proper shadows are cast. Care should
be taken, however, to avoid multiple shadows. By changing the
position of one or more lamps any desired parts of the insect can be
thrown into relief. A useful combination of lights consists of two
photoflood lamps with tracing cloth diffusing screens and a single
spot light. The photofloods are placed on either side of the subject
to give full and uniform illumination and the spot is used to bring
out the desired contrasts.

Back lighting produces interesting results and seems particu-
larly effective in the case of insects having semitransparent wings.
Entirely different effects in wing photographs may be produced by
back, front or cross lighting. An example of cross lighting is shown
in figure 219. This is a photograph of the almost transparent wing

Fig. 218 Transparent Wing of Small Insect:
Front Illumination ; White Back-ground

Fig. 219 Transparent Insect Wing, Cross-
Illuminated Against Dark Back-Ground

322

Miniature Monsters

of a small insect. The beam from a single spot light was directed
across the surface of the wing in order to make the wing veins
stand out in relief. In contrast to this, front lighting against a
white background silhouettes the veins (fig. 218).

Many pitfalls will be encountered. The smooth shiny body of a
beetle will reflect brilliant patches of light. Undesirable reflections
will be produced by the eyes. The under side of the insect will
appear on the print as a black area with no detail unless care is
taken to place one or more lights at the level of the insects body or
slightly lower. Many other difficulties will be encountered which
can be solved only by experiment. In general, most of the lighting
principles which are used in portrait work apply equally well to
the photography of insects. The difficulty lies in the practical appli-
cation of these principles. The subject is so small and the effects
of the lighting are, in consequence, so difficult to judge that many
times it is only when the final enlargement is made that the correct-
ness of the lighting arrangement is known.

Ultraviolet Light

If extreme resolution of detail is required it will be necessary
to depart from the usual sources of artificial light and to take advan-
tage of the short wave lengths of the ultraviolet region. An inspec-
tion of the equation for resolving power of a lens will show that
decreasing the wave length of the light used increases the resolving
power.

The use of ultraviolet light for photography immediately sug-
gests quartz lenses and quartz lamps, but these are very expensive
and are not necessary for ordinary work. The usual types of camera
lenses will transmit wave lengths from the visible spectrum down to
about 3300 Angstrom units which is sufficient to give a noticeable
increase in definition.

A convenient and relatively inexpensive source of light is the
Black Bulb ultraviolet lamp manufactured by the "Westinghouse
Lamp Company and obtainable through any of their local offices.
It is a mercury vapor lamp equipped with a standard screw base.
It operates at 15 volts and comes in two sizes having 2 amperes and
5 amperes current consumption respectively. The lamp transmits
ultraviolet wave lengths from 3200 to 4200 Angstrom units, which
are the long waves of the ultraviolet region and which, incidentally,
are of high actinic value in photography. They ai?e not harmful to
the eyes.

323

Great care should be taken not to connect these lamps to the
usual 110 volt house lighting circuit as they will immediately burn
out. They should always be used In series with a suitable reactance
or resistance depending upon whether they are to be connected to an
alternating or a direct current source.

It is advisable to use two lamps in order to obtain balanced
lighting of the subject, and the exposure time will be reduced if they
are used with reflectors. In selecting these it should be remembered
that a reflector which is quite satisfactory for white light will not
necessarily serve for ultraviolet. Probably the best compromise be-
tween reflection efficiency and availability of the material is aluminum
oxide. This may be formed on the surface of any aluminum re-
flector by immersing it in a strong solution of lye. It should be
removed and washed for examination at intervals of two or three
minutes and the action should be continued until the aluminum has
a uniform matte surface. Just two words of caution — first make
sure that the reflector purchased is not chromium plated on the
inside, and second, do not breathe the fumes .of the lye bath.

The visible light from the Black Bulb is so faint that focusing is
impossible and must be done by white light. While theoretically the ultra-
violet will cause a shift of focus, practically this is so small that it is not
noticeable in the finished picture. The exposure time will be much longer
than with the usual sources of artificial light. Definite comparisons are dif-
ficult because of the lack of a convenient means of measuring the intensity
of the ultraviolet light but the following may serve as a rough guide:

Two sets of exposures of the same subject were made, using in one case
two Black Bulbs in aluminum reflectors and in the other case one small spot
light equipped with a 100 watt projection bulb. The lights in each case were
placed at about the same distance from the subject. To produce negatives
of equal density required about 150 times as long an exposure with the ultra-
violet as with the white light.

The improvement in definition resulting from the use of ultraviolet light
is shown in figures 220 and 221, These are photographs of the eggs which

Fig. 220 Eggs of Canker Worm Fig. 221 Same Section of Egg Mass

Photographed by Ultra- Violet Light Photographed by Mazda Light

324

Miniature Monsters

produce the inch or canker worm so destructive to foliage. Tlie pictures
were taken on the same roll of film with the same lens so that all condi-
tions except the light source were identical.

Increased definition is only one of the results of the use of ultraviolet.
Experiments conducted by Dr. Frank E. Lutz and others indicate that insects
see by ultraviolet rather than by the light to which our eyes respond. By
using the short invisible waves to photograph the insects we are able to
picture them as they possibly look to each other. Comparison photographs
of the same insect taken by white and by ultraviolet light will in some cases
reveal interesting differences in the marking. Figures 222 and 223 show
two photographs of a butterfly taken in one case by white light, and in 'the
other by ultraviolet.

Fig. 222 Yellow Tiger Swallow-Tail But-
terfly. Photographed by Mazda Light

Fig. 223 Same Butterfly. Photographed
by Ultra- Violet Light

The determination of the best film to use in ultraviolet photography
must be left to the reader to determine, as the writer has not yet had time
to make complete comparative experiments. Dupont Superior Panchromatic
with which the accompanying illustrations were made has given excellent
results, although possibly other films may be found which are better suited
to this light.

Equipment for Indoor Work

In preparing the photographic apparatus for indoor use, the
camera should be so mounted that the axis of the lens is horizontal,
and both the camera and the platform upon which the insect is placed
for photographing must be mounted very rigidly in order to elimi-
nate vibration and consequent loss of definition. As the amount of
photographic magnification is increased this becomes a serious prob-
lem and unless the whole structure is very rigid every nearby truck,
train or street car will cause noticeable vibration. Another matter
of importance is to support the extension tube at a point near the
lens. If this is not done the vibration will be excessive no matter
how firm the remainder of the structure may be.

One of the arrangements used by the writer is shown in figure 224. The
bed on which the equipment is mounted consists of two 5-ply hard wood
panels bolted together and weighing about 40 pounds. Sponge rubber

325

Fig:. 224 James M. Leonard and his Camera Equipment for the Photog-
raphy of Insects

blocks are placed between the panel and the table top to absorb vibration.
The table itself rests on cork. The camera is attached to a tripod head from
an old German machine gun mount. These can be picked up in some of the
stores dealing in second hand war material. The various adjusting screws
on the tripod head make it possible to raise or lower the camera, to rotate
it from side to side, and to tilt it in any direction.

The mounting bed carries a heavy walled brass tube which is strongly-
braced and on which are two Leica sliding arms. The outside diameter of
the tube is lx/4 inches which is the correct size to fit the sliding arms. A
small platform on which the insect is placed for photographing is mounted
on one arm and the other is used to support the backgrounds. The platform
can be moved forward or back by means of a rack and pinion. A movable
support for the end of the extension tube rests on the mounting bed.

Photographing at Home

The insect to be photographed is placed on the platform and
the sliding arm is moved to get about the proper working distance
between the lens and the insect. The fine focusing adjustment is
made by means of the rack and pinion.

Having put the insect in place and arranged the lights all that
remains to be done is to focus, expose, develop and print. These few
operations, however, bring up some very interesting problems. For
example, the question of the proper diaphragm opening is a vexing
one and usually resolves itself into a compromise between depth of
focus and definition. Stopping down the diaphragm increases depth

326

Miniature Monsters

Fig. 225 Amblicorypha Oblongifolia — A Relative of the Katydid

of focus but in the case of some lenses results in a loss of definition.
Opening it, may increase the resolving power but gives almost no
depth of focus. A fairly wide open diaphragm may be permissible
when photographing an insect 7s head or other part which will not in-
clude the foreground or the mount on which the insect is placed. If,
however, these are included in the picture the result will be far from
pleasing. The foreground will show a clean cut section which is in
sharp focus while everything in front of and beyond this section
will be completely out of focus. As the diaphragm is closed the sec-
tion in focus will widen and the line of demarcation between it and
the out-of -focus area will grow less distinct. The optimum opening
is reached when the areas which are in focus and those which are
not blend into each other; the important parts of the insect being,
of course, in focus.

Some difficulty may be encountered in determining whether or
not the insect is sharply focused because of the small amount of light
reaching the ground glass when the diaphragm is partially closed or
when several sections of extension tube are used. Focusing will be
made much easier if the ground glass is given a light coating of oil.

327

Fig. 226 (left) The Poison Sting at the End
of a Scorpion's Tail

Fig. 227 The original Zipper Purse— The
Egg Case of a Cockroach

Coeoanut oil is very satisfactory for this purpose. Place a drop on
the ground side of the glass and spread it with the finger, rubbing
lightly in one direction and then at right angles to that direction to
insure even distribution of the oil. Do not use cloth to spread the oil
because pieces of lint are likely to adhere to the glass. Wipe the
surplus oil from the finger after each rubbing in order to reduce the
film to the right thickness. The proper amount remains when objects
several feet distant appear indistinct when viewed through the glass.
Exposure

The proper length of exposure can best be determined by the
trial and error method. An exposure meter will help, but the subject
being photographed is so small that the amount of light which it
reflects toward the lens is insignificant compared with the light re-
flected by the mount or the background. About the only way to be
sure of getting a usable negative is to make four or five exposures
of each subject. The first exposure should be somewhat shorter than
the estimated correct time and each succeeding exposure should be
V/2 or 2 times the preceding one. A record should be kept of the
subject, the lighting used, the length of the extension tube, the dia-
phragm opening, and the time of each exposure. A study of such a
record will soon enable the experimenter to make a sufficiently good
guess at the exposure time so that if not more than three exposures
are made as just described one of them will produce a negative of the
correct density.

The table on page 198 will be very helpful in determining the relative
exposure for any length of extension tube and includes other valuable in-

328

Miniature Monsters

formation as well. Also consult the chapter on Copying and Reproduction,
by Willard D. Morgan, for information on other lenses and on depths of
focus.

^ Any reference to films and developers may seem unnecessary. These
subjects have been fully covered in many publications. A few personal opin-
ions will be ventured, however, in the hope that they may help the beginner
in insect photography. If extreme definition is desired the order of pref-
erence probably should be (1) positive film, (2) orthochromatic and (3)
panchromatic. If proper rendition of the colors is the first consideration
the order should be reversed. Many insects, particularly the moths and but-
terflies are marked with red or orange and if the various gradations and
shades of these colors are to appear in the finished print the use of pan-
chromatic film is essential.

Fig. 228

Fig. 229

The Life Cycle of the Spice-bush Swallow-tail Butterfly

Fig. 230

329

The writer has adopted DuPont Superior panchromatic film and the
so-called Sease No. 3 developer for his own use. The formula for this
developer has been published many times but will be repeated here for the
sake of completeness.

Sodium Sulfite 3 oz. 76 grains 90 grams

Paraphenylene Diamine . . . 154 grains 10 grams

Glycin 93 grains 6 grams

Water 33 oz. 1 liter

Developer at 68° F.

Gamma in fourteen minutes 0.62

Gamma in tWenty-eigrht minutes 1.09

Gamma in forty-two minutes 1.34

Time to reach 0.7 gamma 17 minutes

While this developer has the disadvantage of requiring approximately
double exposure it has the advantage of excellent keeping qualities and of
producing fine grain. The writer has developed twelve rolls of film in a
liter over a period of months and the developer still appeared to be in good
condition.

It is hoped and believed that those who take up insect photog-
raphy will find it a fruitful source of enjoyment and relaxation. The
use of a little imagination in departing from the usual procedure of
photographing the entire insect will produce interesting, and some-
times amusing results. A collection of insect portraits may be made,
or individual parts of the insect, rarely seen in detail by the unaided
eye, may be photographically enlarged. Figure 225 is a typical insect
portrait, the subject, in this case, bearing a surprising resemblance to
the head of a horse. Figures 227 and 226, the egg case of a cockroach
with its zipper top, and the poison-sting which is the scorpion's weapon
of attack, are examples of parts of insects so enlarged that their
details may be seen. Caterpillars found in the garden or the field
may be brought home to develop their fascinating and mysterious life
cycle within reach of the camera. Figures 228 to 231 show "four
stages in the life cycle of Papilio-troilus, the Spice-bush Swallow-tail
butterfly. These few suggestions by no means exhaust the possibilities
of this interesting branch of photography. The field is limited only
by the bounds of imagination.

Fig. 232 Portion of Fig. 229. Who
is the Father of our Country?...

330

PHOTOMICROGRAPHY

THE

H. W. ZIELER CHAPTER 19

The Leica camera, the pioneer of miniature cameras has opened
so many new fields to photography and has been used successfully for
so many different tasks where it replaced larger cameras, that it is not
surprising when it enters the field of photomicrography.

It has become well known that for certain types of photography
the miniature camera is directly essential, due to special optical condi-
tions which are verified in this kind of camera. The combination of
high speed of the objective and depth of focus in the picture which
has been thoroughly discussed in the chapter on lenses, establishes the
necessity of miniature cameras for many special tasks such as candid
photography, photography of small objects, stage photography and
others. For these purposes the miniature camera is essential because
it does what no larger cameras can do. When trying to use the Leica
camera for photomicrography it may appear upon superficial con-
sideration that something paradoxical is being attempted. If small
objects are to be photographically reproduced at a high ratio of magni-
fication, it seems necessary to have a large negative, rather than crowd-
ing the enlarged detail again into a small negative. The sceptic may
readily admit that photomicrography with a miniature camera is not
altogether impossible but he may consider it more or less useless or
unsatisfactory and, at any rate, not specifically advantageous. It is
interesting that a closer investigation of the optical principles proves
beyond doubt that for certain types of photomicrography the miniature
camera is essential and it is only with its help that some apparently
unsurmountable difficulties can be solved.

When to Use the Leica for Photomicrography

In order to fully appreciate why the Leica camera can be used for
photomicrography and why it may be the only means towards achiev-
ing success, we must again dive into several intricate optical problems.

331

Some of them have been thoroughly explained in the chapter on Leica
lenses and need only short recalling.

To begin with, we must realize that the very purpose of pho-
tomicrography is to record minute detail which is so small that it
must be magnified in order to become visible. In the microscope there
are two lens components which participate in the process of magnify-
ing, and in taking the photomicrograph a third factor enters to make
the process complete :

1. the microscope objective forms a magnified image of the object
under investigation

2. the eyepiece of the microscope remagnifies this image

3. the distance between the eyepiece and the negative on which the
picture is recorded determines the area which the magnified image
finally occupies in the photograph.

It is interesting and important to know, that only the first of
these three stages of magnifying is capable of revealing finer detail.
The function of the eyepiece and the projection distance in recording
the image on the negative is comparable to an enlarging process. In
the enlargement we find the same detail which was in the negative but
stretched over a larger area to bring it within the limit of visibility of
the eye. Every single detail which we find in the enlargement was
also in the negative, only it may have been so close together that the
eye could not see it.

In photomicrography we find all revealable detail in the first
magnified image which the objective produces. In this image, how-
ever, the detail is crowded into such small space, that considerable
enlargement is possible before it is fully detectable by the human eye.
We could place the negative in the plane where the objective has
formed the first magnified image and simply enlarge this negative
with a regular enlarging apparatus. In doing this we would meet with
some technical difficulties. In the first place the grain size of the silver
deposit in the finished negative would limit us in producing greatly
magnified enlargements. And then, as was mentioned in the chapter
on lenses, there is always a certain loss of detail in recording the image
on the turbid emulsion of the film. The light, in penetrating through
this layer, is scattered and thus the rendition of detail is slightly
decreased.

Therefore it is advisable to call for the assistance of another optical
unit to participate in the process of enlarging the image which the
objective has formed. But although we can let the eyepiece carry the

332

Photomicrography

entire burden of the enlarging process so that in the original negative
we find the detail separated far enough to make it visible for the eye
(in which case a contact print could be made from the negative) we
may, with equal justification, divide the task so that for instance in
the negative the detail is still four times more crowded than is per-
missible for the eye to see it. In this case we simply enlarge the neg-
ative again four times in our regular enlarger.

The realization is of utmost importance. We must not forget that
any process of magnifying is naturally connected with a reduction of
the light intensity in a given area. In fact, the light intensity de-
creases with the square of the size of the negative so that for instance
in taking a photomicrograph on a plate of 5 x 7 inches we require an
exposure which will be 25 times as long as that which a Leica negative
(1 x 11/2 in.) requires if it is placed so much closer to the eyepiece, that

Fig. 233 Amoeba Dubia
lOx Objective, 8x Eyepiece

Fig. 234 Chaetogaster
3x Objective, 8x Eyepiece

C. G. Grand

the same area of the object is reproduced on it. There are many occa-
sions where a short time of exposure in a photomicrograph is essential
because the specimen under the microscope may be living and moving
around so that it can only be photographed by instantaneous exposure.
Often it is not possible to increase the intensity of the light by selec-
tion of a stronger light source because the enormous concentration of
light in the plane of the object may quickly destroy the delicate struc-
ture of the specimen. In these cases there is just one solution : the
miniature camera. It is not surprising that it was the important field
of photomicrography of living objects which came to its full practical
significance only through the miniature camera.

But, whereas the miniature camera is indispensable for this type
of photomicrography, it can also be used with great convenience for
many tasks of general photomicrography without serious disadvan-
tage. Whenever a great many photomicrographs have to be taken
under identical light conditions and magnification, it is, of course, a
great convenience to have the Leica with its gr^at film carrying ca-

333

pacity, its inexpensive negative material and the great variety of
film emulsions. General Photomicrography with the Leica is eco-
nomical and convenient. Only in rare cases will it happen that the
requirements for recording even the very minutest detail, are such
that the method with the small negative may show slightly inferior
results when compared to photomicrographs on larger negatives.

Photomicrography of living objects and general photomicrography
are of great importance for the scientist. But also the amateur can
become interested in it and he can derive an infinite amount of pleasure
from it. So we have a rather popular field of application for the Leica
camera in photomicrography as a hobby,

To summarize, we can form three groups and this classification is
not arbitrary but has quite an important influence upon the selection
of the best equipment :

1. Photomicrography of moving objects : the Leica is a necessity,

2. General photomicrography : the Leica is an economical convenience,

3. Photomicrography as a hobby: the Leica is a source of pleasure.

How to Adapt the Leica Camera to the Microscope

In describing the technique of photomicrography with the Leica
camera we must, of necessity, give preference to those details which
relate specifically to the camera. The problems pertaining primarily to
microscopy must be treated more briefly, because we wish to condense
the information into a chapter rather than into a library. Therefore
we shall, for the present, consider the microscope as one unit, and the
Leica camera as another one and then describe the best method of com-
bining these two units for the various purposes of photomicrography.

Among the accessories offered for the Leica camera, there are
devices which permit three different ways of adaptation of the camera
to the microscope. Which of these three devices should be used,
depends again upon the type of work which we want to do.

Fig. 235 Daphnia Pulex

C. G. Grand

2x Objective, 8x Eyepiece

334

Photomicrography

Photomicrography of Living Matter with the
Micro Ibso Attachment

When using the Micro Ibso attachment, the regular Leica lens must
be removed from the camera. That means that this attachment can-
not be used with Leica Model
A. The attachment, shown
in figure 236 is to be adapted
to the camera body like a reg-
ular Leica lens. At its lower
end it is equipped with a
microscope eyepiece. This eye-
piece has a magnifying power
of 10x when used for visual
observation. Used in connec-
tion with this device, however,
this power is not fully devel-
oped because the small nega-

ms. 236 Micro-Ibso Attachment with syn- tiv6 °f the Lelca Cam6ra ls
chronized cable releases : one activating the Com- placed SO close to the evepieee.
pur Shutter, the other throwing the prism out ^ J ^

of the path of light rays The microscopist knows that

only if the negative is placed 10 inches from the eyepiece, the mag-
nification of the latter in photomicrography will be equal to that
which prevails in visual observation. With the Ibso attachment the
eyepiece does only one-third of its performance for visual observa-.
tion. But this is just enough to spread the detail conveniently over
the area of the Leica negative. That means that a Leiea negative,
enlarged to the size of 3 x 4% inches will represent a photomicrograph
with the same magnification as that which prevailed if the same ob-
jective and eyepiece would have been used for visual observation.

The eyepiece can be removed from the Ibso attachment by un-
screwing the knurled adapter ring with which the entire device is
clamped to the microscope tube. It is not advisable to use eyepieces

of different magnifiying power. It
must be realized that the field seen
through the microscope is circular
whereas the shape of the negative is
rectangular. On the other hand we
find in photomicrography that it is

Fig. 237 Leica Photomicrograph
made with the Micro-Ibso Attach-
ment

335

often next to impossible to have the entire field appear uniformly
sharp in focus. Especially at higher magnification the outer portion
of the field is more or less out of focus. The eyepiece with which the
Ibso attachment is equipped has such magnifying power that the most
valuable portion of the field is utilized. How the image of the speci-
men fills the frame of the Leica negative is shown in figure 237.

Fig. 238 Micro-Ibso Attachment with Leica camera
placed upon Microscope — -ready to use

The middle section of the Ibso attachment contains a beam-
splitting prism which can be removed from the course of rays by
operation of a wire release. So that this prism may also be held
outside of the course of rays, the wire release is equipped with a clamp-
ing screw. A certain portion of the light which has passed through

336

Photomicrography

the microscope is reflected by the prism into a side telescope where the
micro image can be visually observed and focused. The balance of the
light passes onto the film. Above the telescope there is a Compur
shutter with which the actual exposure is made. A conical housing
is attached to the middle section and this is of such length that the
image will fill the negative as shown before. This housing also con-
tains a lens system for the purpose of correcting the passage of the
rays so that at this short distance a sharp image can be produced.

It is the beam-splitting prism and the side telescope which make
the Ibso attachment so valuable for photomicrography of living
objects. When the specimen is in motion it is essential that we
have a method of observing and focusing continuously until the very
instant before the exposure is taken and these two features enable us
to do so.

And in order to shorten the time of exposure as much as possible
we do not only benefit from the small negative size of the Leica but
also from the fact that during the (general instantaneous) exposure
the beam-splitting prism is removed from the course of rays, thus con-
veying the entire available amount of light onto the film.

The side telescope is equipped with an adjustable eyelens. This
is an important device which is often overlooked. When focusing
visually we must realize that there are differences in the eyesight of
different observers. When the image appears in focus for one ob-
server, it may not be sharp for another; yet the image must always
be sharp in the plane of the film. These differences are compensated
by the adjustable eyelens. In looking through the side telescope a
cross hair ruling is visible. Before focusing the microscope the ob-
server must turn the mount of the adjustable eyelens until the cross
hairs appear in perfect focus. Only when this is done should the
microscope be focused with the coarse and fine adjustment. In this
case there will aways be coincidence of focus in the side telescope
and in the plane of the film. If a different observer looks through
the side telescope and finds the micro image out of focus, the cross
hairs will likewise lack in sharpness. But simply by turning the
mount of the adjustable eyelens crisp focus can be established for
both, the image and the cross hairs.

It may appear strange that a Compur shutter is required to
take the photo inasmuch as the Leica camera has a focal plane shutter.
This shutter, however, when released, moves in a direction which
would create a lateral momentum and cause vibrations which would
affect the sharpness of the picture. The Compur shutter avoids this

337

danger. But since the transporting of the film is coupled with the
winding of the Leiea shutter, the procedure of taking successive
photomicrographs is somewhat complicated and the photomierographer
will have to accustom himself to the following sequence of manipula-
tions.

1. Remove the lens from your Leica camera and adapt in its place the
Micro Ibso attachment to the camera body of Leica models C, D, E,
F, FF, or G.

2. Remove the regular eyepiece from the microscope tube, set the tube
to the correct mechanical tubelength prescribed by the manufacturer
(some microscopes are equipped with draw-tubes, others have sta-
tionary tubes; the manufacturers have different standards as to the
length of the tube and when the microscope is equipped with a draw
tube, this must be correctly set) and place a rubber ring or metal
clamp around the draw-tube so that the weight of the camera with
Ibso attachment will not change the tubelength. A rubber ring is
supplied with the Ibso attachment.

3. Adapt the Ibso attachment with Leica camera to the microscope by
inserting the eyepiece of this attachment into the microscope tube.
Then tighten the clamping1 screw on the knurled ring at the lower end
of the Ibso attachment.

4. Fasten the two wire releases to the Ibso attachment. The one with
clamping screw is for the beam-splitting prism, the other one is for the
Compur shutter.

5. Attach the regular wire release to the Leica camera. Wind the focal
plane shutter of the Leica camera and set it for time exposure.

6. Adjust the eyelens of the side telescope so that the cross hairs appear
in sharp focus.

7. Focus the image of the microscope with coarse and fine adjustment
while looking through the side telescope.

8. Set the Compur shutter for the correct time of exposure.

9. Press the wire release of the Leica camera and clamp the wire release
in this position so that the focal plane shutter will remain open. You
are now ready to take the exposure by pressing the wire release of the
Compur shutter. If you wish to have as much light as possible for
the exposure, you can also swing the beam-splitting prism out of the
course of rays. Thus you will have to operate two wire releases simul-
taneously. But you must also operate the fine adjustment of the
microscope continuously and since we have only two hands, you may
wish to make use of an automatic release attachment which permits
with one motion to swing out the prism and immediately afterwards
to take the exposure. This attachment is likewise shown in fig. 238.

10. After the exposure has been taken, loosen the clamping screw of the
Leica wire release, thus closing the focal plane shutter. Wind to the
next frame, press the Leica release again, clamp it in this position
and you are ready for the next picture.

Whereas the Ibso attachment can, of course, be used for every
task in photomicrography with the Leica camera, regardless of whether
the object is moving or stationary, other devices may be preferred in

338

Photomicrography

the latter case. The Ibso attachment, after all, is not inexpensive and
other Leiea accessories may be used equally well, having the added
advantage of the possibility of other applications.

General Photomicrography with the Sliding Focusing Attachment

Excellent photomicrographs can be taken with the Leica camera
adapted to the sliding focusing copy attachment when the latter is
attached to the extension arm on the upright of the Valoy enlarger
(or other models) and is provided with an extension tube of a certain
minimum length. Also in this case, Leiea Model A cannot be used
because the camera body alone must be attached to the focusing at-
tachment. The general set-up is shown in figure 239. After having
removed the lamp housing from the upright of the enlarger, the spe-

Fig. 239 General set-up showing how a Sliding Focusing Attachment is
used with the Leica for Photomicrographic work.

cial arm which holds the focusing attachment with the Leica camera
is fastened to the upright. An extension-tube of 6cm, should be used
attached to the sliding focusing attachment. The arm carrying the
entire Leica equipment is lowered until microscope tube and extension

339

tube just overlap. A light-proof connection can easily be established
by wrapping a piece of black paper or cloth around the lower end of
the extension tube. *

It is, of course, possible to use extension tubes of any length. The
total length of the tubes used will determine the magnification of the
image in the plane of the film and therefore also the area which the
image occupies. A tube of 6cm. has been suggested for definite rea-
sons. When this tube is used, the image will occupy about the same
area as that shown in fig. 237, when an eyepiece of 10s magnifica-
tion is used, as in the ease of the Ibso attachment. It is also possible
to use eyepieces of different magnifying power. When these eyepieces
are used for such short projection distances they do not yield their
total magnifying power which would prevail in visual observation.
Only if the total distance from the rim of the eyepiece to the plane of
the film is 10 inches will the eyepiece yield the same magnifying
power as in visual observation. For shorter distances this power
decreases correspondingly. When the total distance is only about
3 1/3 inches (as it will be when the 6cm tube is used) the eyepiece
magnification is also reduced to 1/3 of its full value, which corresponds
to that which we use when taking photomicrographs with the Ibso
attachment.

For those who want to proceed in strictest accordance with cor-
rect optical principles it may be mentioned that when taking photo-
micrographs with the focusing attachment, they may use eyepieces
with adjustable eyelenses to compensate for the short projection dis-
tance. The principle involved is too complicated and the benefit de-
rived too minute to require special explanation. The reader who is
interested is referred to literature about microscopy.

The procedure in taking photomicrographs with this equipment
is as follows :

1. Before placing the focusing attachment with Leica camera and exten-
sion tube in position, focus the microscope roughly for visual observa-
tion so that the microscope tube will not have to be displaced too much
in vertical direction after the light-proof connection has been estab-
lished.

2. When the microscope has been focused visually, lower the arm on the
upright until the extension tube overlaps the microscope tube and make
the light-proof connection. Tighten the clamping screw on the exten-
sion arm when the image on the ground glass appears as shown in
figure 2 (provided a lOx eyepiece and 6cm tube were used).

3. Attach the wire release to the Leica camera.

4. Focus the image sharply on the ground glass by means of the fine
adjustment of the microscope and slide the Leica camera into position.
You are now ready to take the photomicrograph.

340

Photomicrography

When the focal plane shutter is released there Is no danger of vibra-
tions affecting the sharpness because the Leica camera is held rigidly in
the focusing attachment.

Obtaining Critical Focus

Critical mieroscopists may resort to a simple trick in order to
avoid any error in focusing on the ground glass. A small piece of
thin clear glass, such as a cover glass, used for protection of micro
slides, may be pasted to the ground glass with a small droplet of cedar
wood oil. The covered area will become transparent and the aerial
image may be focused with a special 30x magnifier (a special ground
glass with a clear strip and calibrated scale is also available). This
magnifier, however, must also be focused to the plane of the cover-
glass. Therefore, before attaching the coverslip, a small pencil mark
should be made on the ground glass. The magnifier may be raised or
lowered in its mount until this pencil mark appears in sharp focus.
Then the fine adjustment of the microscope must be operated until
the micro image also appears in sharp focus.

The results which can be obtained with this equipment are so
satisfactory that for many purposes of general photomicrography it
finds more and more extensive use. As long as stationary objects are
to be photographed it is often preferred to the Ibso attachment be-
cause it seems easier to obtain a critical focus although with some
training the other method yields equivalent results.

There is another method of photomicrography with the Leica
camera which requires less equipment. This method may be sug-
gested to the amateur who may not wish to go too deeply into this type
of work.
Amateur Photomicrography with the Micro Adapter Ring

"When using the Leica camera with the micro adapter ring the
lens must be left in the camera. Therefore it is also possible to use
Leica Model A for this type of photomicrography. The micro adapter
ring is slipped over the tube of the microscope and its upper part is so
shaped that it can be adapted to the rim of the Leica lenses of 50mm
focal length like a light filter.

The method of focusing is as simple as it is interesting. Focus
the microscope for visual observation, focus the Leica camera inde-
pendently for infinity and then place it over the microscope into the
micro adapter ring where it is held in place by tightening the clamp-
ing screw in the upper part of the adapter.

This method of focusing is so interesting because it reminds us of
the fact that the human eye is really a very small miniature camera,
perhaps the most remarkable miniature camera in existence. The

341

human eye is equipped with a lens which forms images on the retina.
But this lens has no focusing mount and yet it can be focused. It is
certainly a most wonderful creation. Since nature preferred not to
provide our eyes with bellows or focusing mounts which would permit
to change the distance between the lens and the retina, the lens in
the human eye focuses itself automatically by changing its focal
length according to the distance from which we look at the object.
When this distance is small, the lens increases its curvature (eon-
trolled by a most ingenious mechanism of muscles) to shorten fts
focal length until the image is sharp on the retina. If the object is
farther away the muscles relax and decrease the curvature to increase
the focal length just enough to have again a sharp image on the
retina. And this complicated mechanism works so perfectly that we
operate it unconsciously and instantaneously as soon as we open our
eyes.

Nevertheless it is a strain for the eye when it looks at an object
at close distance whereas it relaxes as much as possible when it
looks at an object which is infinitely far away. And since the
microscopist must often look through the instrument for long pe-
riods at a time the scientists designed the optical equipment of
microscopes so that the eye can be as much at ease as possible. In
other words the lens in the eye focuses itself as if it would have to
look at an object at infinity. And if we replace the human eye by
another miniature camera (or, for that matter, by any photographic
camera, regardless of size) the lens of this camera must likewise be
focused to infinity.

Not every observer has perfect eyesight. Some are near sighted
others are far sighted. That means that their focusing mechanism
is out of order. Such defects may happen to the focusing mechanism
of other miniature cameras. But as long as we deal with manufactured
cameras we can send them to the manufacturer for readjustment. He
can determine the amount of the error and can either place an inter-
mediate ring under the objective mount or he can shorten this mount
until the images are always in focus if we operate the focusing
mechanism with the rangefinder. Unfortunately there are no similar
repair shops for our eyes so that we must content ourselves with a
correction of the discrepancy by adding front lenses which we call
spectacles, to the lens of the eye. And everybody who must wear
eyeglasses for correction of defects of his eyelenses, should always
leave them on when focusing the microscope visually before taking
pictures with the Leica and Micro Adapter Ring,

342

Photomicrography

Before adding the weight of the Leica camera with adapter ring
to the microscope it is also advisable to attach a rubber ring or a
metal clamp to the draw tube of the microscope at the correct length.

The distance between the Leica camera and the microscope is
now so small that the magnifying power of the eyepiece is still
further reduced to only one-fifth of its power for visual observation.
In other words, if the Leica negative is enlarged five diameters the
final print will represent a photomicrograph which has the same mag-
nification which would have prevailed in visual observation with the
same objective and eyepiece. Figure 241 shows the relation between
the Leica negative and the area covered when taking a photomicro-
graph with the micro adapter ring, using an eyepiece of 12x magnifica-
tion. Eyepieces of different magnifying power can also be used, but
sometimes it will be difficult to avoid internal reflections within the
optical system.

Fig. 240 Placer Gold. Photomicrograph
by R. E. Head, made with Ultropak and
Leica

Fig. 241 11/eica used with Micro
Adapter Ring and 12x Eyepiece
covers area shown

The procedure of taking photomicrographs with the Micro
Adapter Ring can be summarized as follows :

1. Set the draw tube of the microscope to the correct length and fasten a
rubber ring1 or metal clamp so that this tube length will be maintained
when the Leica camera is placed into the Micro Adapter Ring.

2. Detach the black lacquered upper part of the Micro Adapter Ring from
the lower metal part, withdraw the eyepiece from the microscope tube,
fasten the lower part of the ring to the tube and tighten the clamping
screw.

3. Insert the eyepiece into the microscope tube and attach the upper part
of the Micro Adapter Ring.

4. Focus the microscope for visual observation.

5. Focus the Leica camera independently for infinity. Attach the wire
release and wind the shutter which must subsequently be set for the
correct time of exposure.

6. Attach the Leica camera carefully to the upper part of the Micro Adapter
Ring and tighten the upper clamping screw. You are now ready to take
the photomicrograph.

343

Those who possess an enlarger and an extension arm may prefer to
attach the Leica camera to this arm, place the microscope with the adapter
ring on the baseplate of the enlarger and lower the arm until the Leica
lens mount connects with the upper part of the Micro Adapter Ring. Thus
the weight of the Leica camera does not rest on the microscope. This has
not only the advantage of avoiding the danger of vibrations when releasing
the shutter but also that of affecting the accurate focus, especially at high
magnifications.

This method of photomicrography with the Leica camera, incidentally
is optically the most correct one because the microscope retains the same
focus as for visual observation and the correction of the entire optical
system of the microscope is at its best under these conditions.

How to Select the Microscope

For Photomicrography of Living Matter

Whereas prepared microscopic specimens are generally mounted
on glass slides as thin sections and can be observed by sending light
through, them, living organisms or unprepared objects are mostly
more or less opaque and of irregular shape. They not only require
a microscope stand of special design but also special illumination
arrangements. These illumination devices also influence the design
of the microscope.

As long as these opaque objects are to be photographed at low
magnification the illumination offers no difficulties. Under these con-
ditions the distance between the front lens of the microscope objective
and the object is comparatively long. (This distance is generally
called working distance, a term which should not be confused with the
focal length of the objective) . The light emitted by a suitable micro-
scope lamp may be concentrated by a so-called bull's eye condenser
and may be so guided that it falls obliquely upon the surface of the
specimen. But as the magnification increases the working distance
decreases so rapidly that even at moderately high magnification there
is not enough clearance between objective and specimen to squeeze
the light between the two.

Microscopists who examine the surface structures of metals use
a device known as vertical illuminator. It is attached to the lower
end of the tube. The light, entering laterally, is reflected into the
direction of the optical axis of the microscope and passes through the
objective which simultaneously acts as a condenser, to concentrate the
light in the plane of the object. From the surface of the object the
light is reflected and passes again through the objective which now
acts as an image forming unit.

This method of illumination, which yields satisfactory images of
the highly reflecting polished and plane surfaces of metals, fails if

344

Photomicrography

applied to the illumination of rough low reflecting and uneven sur-
faces of organisms or other materials. As the light passes through
the objective on its way to the specimen, partial reflections occur
at the surfaces of the different lenses which produce a haze thus
greatly reducing the contrast in the image. This haze may even
obliterate the detail completely.

The situation can be compared with one which you undoubtedly
have often observed: a picture hanging on the wall may be covered
with a glass plate. Under certain light conditions the glare produced
through reflections of light by the glass plate may be so strong that
you cannot see the picture at all.

Another illumination method was developed for observation of
objects of low reflecting power which avoids the double passage of
light through the objective and can be used even at the highest mag-
nifications. The device used for this purpose, the Leitz UUropak,
was introduced only a few years ago and it has pioneered this im-
portant and utterly fascinating field of microscopic observation and
photomicrography of opaque objects with surfaces of low reflecting
power at high magnification. The illuminator is shown in figure 242.
The light, entering horizontally, is reflected by a ring-shaped mirror
and passes through a condenser system which surrounds the objective.
This condenser collects the light so that it illuminates the object with
highly oblique rays. From the rough surfaces of the object the light
is diffusely reflected, passes through the objective, a central hole in
the ring-shaped mirror and forms the image.

I — Sector diaphragm
I Slit for filters

with Fi£* 242 Bias*8-1*1 showing

aPPara,uS
screwed on

345

The Ultropak is attachable to every standard microscope tube.
It is equipped with a small incandescent lamp which is satisfactory
for visual observation but not strong enough for instantaneous photo-
micrography. In such cases a more powerful light source such as an
arc lamp must be used. A special lens system can be attached to the
light entrance tube of the Ultropak to concentrate this light. The
complete equipment assembled for photomicrography with the Ibso
attachment is shown in figure 243.

Fig. 243 Micro-Ibso Attachment with Microscope and Arc Lamp for Pho-
tomicrography of living matter

This arrangement makes a special type of microscope almost im-
perative. Generally a microscope is focused by raising or lowering
the tube which, for this purpose, is equipped with a coarse adjust-
ment by rack and pinion and a fine adjustment by micrometer screw.
The arc lamp, however, not being attached to the tube, would not
follow these focusing motions and the horizontal beam would not
always pass through the condenser lens which is attached to the
Ultropak. In other words, the operation of focusing the microscope
would throw the illumination system out of alignment. This diffi-
culty can be overcome by using a type of microscope where the
coarse focusing is done by raising or lowering the object stage.

Microscopes of this type provide for much space between the tube
and the stage so that even comparatively large objects may be placed
on the stage in their entirety. These models are recommended for

346

Photomicrography

photomicrography of objects which make the method of illumination
by Ultropak or vertical illuminator necessary. They are of such
design that substage illuminators for photomicrography by transmit-
ted light can be attached to them.

For General Photomicrography

As mentioned before, specimens which have been specially pre-
pared for microscopic observation are generally mounted as thin sec-
tions on glass slides and they are illuminated by sending the light
through the thin layer of the object. The structures may allow only
certain colors of the light to pass through, whereas others are absorbed.
These structures will become visible in those colors which could pass
through them. It may be that other structures absorb all colors
equally, either completely or partly, and those structures will appear
black or any shade of gray against the lighter background. In other
words, the structures become visible because of partial transmission
of light and the illumination method for these objects is generally
called "by transmitted light. The variety of microscopes available for
this type of work is considerable. Essentially all models are built on
the same principle although the various features may differ in regard
to completeness or design. They consist of an illumination apparatus
which guides the light through the object, a stage plate 'to support
the object and an observation system with focusing facilities.

For the selection of a microscope which is to be used for photo-
micrography a few hints may be of value :

The Illumination Apparatus

The mirror which guides the light from its source through the con-
denser should have one plane and one concave surface. The condenser
should be of the divisible type so that the front lens can be removed when
taking photos at low magnification. The illumination apparatus should be
equipped with an iris diaphragm to regulate the intensity of the light.
There should be a rack and pinion movement to raise or lower the con-
denser. It is also advisable to have the condenser mounted in a centering
adapter. When the photomicrographs are taken at high magnification and
microscope lamps with concentrated filaments are used for this purpose, a
centering adapter is of essential importance.

Object Stage

It is convenient, though not essential to have a device for the mechan-
ical displacement of the specimen. Such devices are known as mechanical
stages. They can be obtained either separately or built into the object stage.

Observation System

It has become general practice to classify the ranges of magnification
as follows:

347

low power (requiring objectives from 40 to 16mm focal length)
medium power (requiring objectives from 10-4mm focal length)
high power (requiring objectives of less than 4mm focal length).

For high power microscopy a type of objective is used which is known
as immersion system. Regarding further details about objectives the reader
is referred to the current literature of microscope manufacturers.

The microscope may be equipped with a revolving nosepiece accom-
modating either two, three or four objectives. The objectives of 16mm and
4mm are most popular. For higher magnifications oil immersions of about
2mm are generally used whereas for the lowest magnifications objectives
of 40mm, 32mm, 24mm or thereabout are almost equally popular.

Contrary to general opinion it is not necessary that a microscope for
photomicrography be equipped with a tube of large diameter. A wide tube
may only be of advantage if it is intended to use a microscope for that type
of photography (not photomicrography) which the Leica user can do with
the sliding focusing attachment and the regular Leica lenses. In this type
of work an eyepiece is not required.

It may also be mentioned that it is not advantageous to take
photomicrographs without the eyepiece. Sometimes one meets with
the erroneous opinion that under such conditions sharper images can
be obtained. This is not true. The apparently greater sharpness is
simply due to the lower magnification. Actually such pictures lack in
sharpness because the objective is not used at the correct tube-length
and thus a certain amount of spherical aberration is introduced.

As to the magnification of the ocular, it has been mentioned before
that for general purposes an eyepiece of lOx magnification is most
satisfactory. Variation of magnification in the final print can always
be obtained by varying the ratio of enlargement of the negative.
Only in the case of photomicrography with the micro adapter ring an
eyepiece of 12x magnification may be recommended.

For Amateur Photomicrography

The rules given for the selection of a microscope for general
photomicrography or that of living object can likewise be applied to
amateur work. Only in this latter case a simpler microscope will often
bo fully satisfactory. In this case it is best to see what the manu-
facturer has to offer.

Magnification and Resolving Power

It was explained at the beginning of this chapter that the ob-
jective of the microscope alone is responsible for the revelation of
minute detail and that the eyepiece simply stretches this detail to
occupy a larger area. The power of the objective to reveal detail is
called resolving power and is limited, It is possible to determine for
each objective the magnitude of the finest detail which it is capable
of revealing. And since we can also determine the total magnification

348

Photomicrography

of the image in the negative, we are able to find out how much
space the smallest revealable detail will occupy in the plane of the
negative. This information is important because, as we know from
the chapter about Leica lenses, the human eye can only distinguish
detail if it is at least l/100th inch apart (provided we refer to detail
in a photograph which we view from a distance of 10 inches). Thus
we will finally be able to answer the question: Plow much can we
enlarge the negative of a photomicrograph taken with the Leica
camera without creating the impression that the enlargement will
lack in sharpness?

The maximum resolving power of the objective can easily be
expressed quantitatively by the magnitude of the smallest detail which
the objective can resolve. But in practical photomicrography this
maximum resolving power can seldom if ever be verified, because it
requires certain optical conditions for the illumination of the object
which are detrimental in other respects. Therefore in practice the
obtainable resolving power will mostly remain below this maximum
value.

In the books about microscopy we find that the resolving power
depends upon the light collecting power of the objective and the
wavelength of the light with which the specimen is illuminated. The
light collecting power is generally expressed by a term numerical
aperture. Its meaning is not identical to the relative aperture or
speed of a photographic lens, but has close relation to it. We need
not go into detail about the correct interpretation of the term
numerical aperture because its actual magnitude is generally en-
graved upon the mount of the objective and is also listed in the
catalogs of the manufacturers. "We only have to realize that the
higher the numerical aperture of an objective, the better is its
resolving power.

As to the wavelength of the light, we know that in the spectrum
of visible light, the colors towards the violet end of this rainbow
have the shortest wavelength. But whether we can use these rays for
the illumination of the object, depends entirely upon the colors of its
structures. Further information about the color of the light to il-
luminate the object can be obtained in publications regarding the
application of light filters for photomicrography. For the present
we must only realize that the relation between the resolving power
and -wavelength of the light is such that an objective of a certain
aperture will yield the best resolving power if the wavelength of
the light which illuminates the object is as short as possible.

349

But there is a third factor which influences the resolving power
and which is often neglected in consideration. It refers to the direc-
tion of the light which illuminates the object. As you know, the
intensity of the light which passes through a photographic lens is
regulated by opening or closing the iris diaphragm with which these
lenses are equipped. In a microscopic objective there is no iris dia-
phragm. But we find this iris in the substage of the microscope,
directly below the condenser. If we close this iris diaphragm the
object will be illuminated only with a small central beam of light.
By opening it, the intensity of the illumination increases. But at
the same time the resolving power of the objective also increases.

Still, the resolving power may be increased without opening the
iris diaphragm. We only have to displace it laterally so that the
small beam which illuminates the specimen will not pass through it
centrally, that means, in the direction of the optical axis, but obliquely.

"When to increase the resolving power by opening the iris and
when to displace the iris laterally depends entirely upon the nature
of the structures of the specimen and upon the quality of the objec-
tive. An objective of good quality can be used with the iris diaphragm
comparatively far open whereas in an objective of inferior quality
those misbehaviors of light about which we learned in the chapter on
lenses will make themselves felt too much.

By opening the iris diaphragm we render the illumination more
diffuse and there may be detail which with such illumination will be
obliterated. The surface of a piece of paper may appear smooth in
diffuse light, but hold it in the beam of a powerful searchlight so that
the direction of this light meets the paper surface at grazing inci-
dence, very obliquely. Every little unevenness in the surface will
throw a deep shadow and the little hills and valleys will appear most
strikingly.

These few remarks should indicate that the method of illumina-
tion has a great influence, not only upon the visibility of detail which
may be so small that the highest possible resolving power is necessary
to reveal it, but also because this detail may be of such shape or nature
that special tricks must be applied to render them visible even if they
are large enough to require only little resolving power.

To summarize we may say that under normal conditions the iris
diaphragm of the substage should rarely be opened more than 14 to i/>
of its greatest opening and as to the color of the light we shall learn
presently why a green filter will find most frequent application.
Under such conditions it is safe to assume that the magnification re-

350

Photomicrography

quired to separate the detail until it is about l/100th inch apart, is
about equal to 600 times the value of the numerical aperture of the
objective used.

From the catalogs of the manufacturers we learn the initial mag-
nifications and numerical apertures of the current objectives. We
know that the eyepiece lOx yields about 1/3 of its full magnifying
power when used with the Leica camera as described before and with
this information on hand we can determine how much the Leica
negative of a photomicrograph can be magnified without losing the
aspect of a sharp picture. The following table contains these values
for some of the most popular objectives and may be of help in photo-
micrography.

This table has been prepared for Leitz objectives but by com-
paring the figures for focal length, initial magnification and numerical
aperture with those constants of the objectives of other manufacturers
it will become evident that the figures can be helpful also to users of
other objectives.

Type of
objective

Achromat
(dry)

Apochromat

(dry)
Achromat

(dry)

Apochromat

(dry)
Achromat

(dry)
Apochromat

(dry)

Apochromat
(oil immersion)
Achromat
(oil immersion)
Apochromat
(oil immersion)

Focal
length

40mm

32mm
24mm
16mm
16mm

13mm

9mm

8mm

4mm
4mm
3mm
2mm
2mm
2mm

Initial Mag-
nification of Numerical
objective Aperture

3.2x

4.3x
6 x

10 x
12 x

14 x

20
23

45 x

46 x

65 x

100 x

92 x

O.OS

0.15
0.20
0.25
0.30

0.40

0.45
0.65

0.85
0.95
1.32
1.30
1.32
1.40

Magnifi-
cation on

Leica
negative

10.5x

H,3x
20.0x
33 x
40 x

46.5x

66 x
71.5x

150 x

153 x

216 x

333 x

306 x

Enlargement

possible to

separate

detail 1/100"

4.6 x

6.3 x

6.0 x
4.5 x

4.5 x

5.1 x

4.1 x

5.5 x

3.4 x
3.8 x
3.66x
2.35x

2.6 x
2.75x

Thus we should conclude our chapter on photomicrography be-
cause the problems pertaining specifically to the miniature camera
have been covered. But there are so many questions pertaining to

351

microscopy which the miniature camera owner would like to have
answered that at least some of them shall be briefly discussed.

Light Sources

It is difficult to recommend one definite light source because so
many different types are suitable and yet each of them has special
advantages, depending upon the work which has to be done.

For photomicrography of living objects, for instance, a great
deal of light is required because the image is formed only by that
small portion which is reflected from the surfaces of the object. The
effective intensity of light sources for microscopy, however, is not
measured in terms of total candlepower and it is very important
for the microscopist to understand why we need another measure.
Actually we can compare the power of microscope lamps only in
regard to their intrinsic intensities. This will become evident if we
compare a lamp for 110 volts and 550 watts with one for 6 volts and
30 watts. The only difference is to be found in the length of the
filament, that of the lamp for 110 volts being about 18 times as long
as that of the lamp for 6 volts. In both cases, however, the filament
is fed by a current of 5 amperes and pieces of equal length of the
two filaments emit the same amounts of light. Of course with the
110 volt lamp we could illuminate an area having 18 times the square
contents of that which, with the same condenser system the 6 volt
lamp will illuminate. But the condenser systems are designed for
rather small light emitting units because it happens that among these
we find the light sources of greatest intrinsic intensity.

Of the two light sources mentioned above the one for 6 volts should
of course be preferred because, although it offers the same intrinsic
and therefore effective intensity, it consumes only 1/lSth of the amount
of energy. The fact that these lamps must be used with a transformer
(or a rheostat, if d. e. is available) should not be considered as a dis-
advantage because the lamp fulfills an optical purpose and its per-
formance in this respect is the only important thing.

The intrinsic intensity of a light source increases in proportion
to the temperature of the light emitting area. A filament, heated to
incandescence can never become as hot as, for instance the crater of
an arc lamp where the carbon is heated beyond the point of incan-
descence so that it is actually consumed Arc lamps have a compara-
tively small sized crater and in order to t^able the miscroscopist to
take full advantage of this important type of lamp, the condenser
systems of microscopes are so arranged that this small light emitting
unit will illuminate the entire field under observation. These arc

352

Photomicrography

lamps are often the only type of light source which will make in-
stantaneous photomicrography of opaque living objects possible, even
with the small Leica.

For photomicrography in transmitted light we may not require
these strong light sources. In the first place, the entire amount of
light which is concentrated by the condenser, passes through the
microscope and is only partly absorbed by the structures of the object
which in the photograph will appear darker than the background.
Furthermore, these objects are generally not moving and longer ex-
posures are permissible. In these cases a regular desk lamp with an
inside frosted bulb, possibly a photoflood bulb, will give satisfactory
illumination. Clear glass bulbs, showing the filament, should not be
used, unless a ground glass is interposed.

It is not possible to explain here, how, for every magnification,
uniform illumination can be obtained. The reader must try to obtain
such information from microscope manufacturers or text books. He
will find, that by following definite rules he can avoid the rather uncer-
tain method of trial and error, but these methods would require too
much space in this chapter.

Light Filters

The application of light filters in photomicrography is another
problem which requires thorough study. The reader is referred to
current literature. The Eastman Kodak Co. published a booklet, en-
titled '' Photomicrography ' ? from which valuable information can be
derived.

In the vast majority of cases where stained preparations are to
be photographed, a green filter, such as the Wratten B filter will be of
great help. Not only are most of the stains, used in practice, of such
color that a green filter will produce the best contrast and differentia-
tion, but the light transmitted by this filter is of that range of wave-
lengths for which the correction of microscope objectives is most
favorable.

As to the best place to insert the filter, no special advice is
necessary since it can be inserted at any place between the lamp and
the microscope. It may happen however, that the filter is at a place
where any dust spots or impurities on its surface would show in the
field under observation because the condenser may form an image of
the filter in the plane of the object. If such dark spots are visible,
it is easy to find out whether they are produced by the filter or by
impurities on the lenses of the eyepiece. Suppose we move the filter
laterally and the spots follow the motion, they are caused by dust on

353

the surface of the filter. But if, upon rotation of the eyepiece in the
microscope tube, the spots follow this rotation, they are due to impuri-
ties on the lenses of the ocular. In both cases, the surfaces should be
cleaned, but if the filter gave the cause, it can also be moved closer to
the condenser.

rams

In photomicrography it is often not necessary and even detri-
mental to use panchromatic film of high sensitiveness. The panchro-
matism of the film is not required when a green filter is used. As you
know, the only difference between orthochromatic and panchromatic
film, lies in fact that the latter is also sensitive to red light. But if
the filter has prevented all red light from passing through the micro-
scope, this extra sensitiveness is of no value. On the other hand,
panchromatic films are generally less sensitive for greem light (that is
why green safelights can be used in the darkroom for their develop-
ment) so that their general high speed does not exist for that range of
light color which is transmitted by the filter.

Finally we must realize that these superspeed films really do not
yield that same fine detail which we obtain with slower films. It is
true that the development can hold the grain size down but for reasons
which are too involved to permit explanation at this place, it is really
true that the slower films with inherently finer grain produce finer
detail.

To sum up, any modern orthochromatic film is perhaps most suit-
able for photomicrography. Where speed is essential, the faster emul-
sions are to be preferred, where detail rendition is of primary im-
portance, the slower emulsions are better. Only in cases where living
objects are photographed with the Ultropak or a darkfield condenser
and if in these cases no filter is used, a fast panchromatic film will
have its place.

In exceptional cases positive film may be used. But we must not
forget that this film is not sensitive to green light. Used when the
Wratten B filter has been interposed in the course of rays, a photo-
micrograph on positive film would only yield a blank space. Without
a filter, the positive film in itself will perform what a blue filter would
have done with orthochromatic film. This fact may be helpful in
photomicrography of diatoms where the utmost in detail rendition is
aimed for. But this task is perhaps one of the very few, where the
miniature camera actually does not offer anything but disadvantages
over the larger size cameras.

354

Photomicrography

Exposure

Help in gauging the exposure for a photomicrograph is perhaps
most urgently needed and it is unfortunate that just in this respect it
can hardly be given. The exposure depends upon too many different
factors. There is the intrinsic intensity of the lamp, the size of the
filament, the opening of the iris diaphragm in the substage, the magnifi-
cation of objective and eyepiece, the numerical aperture of the objec-
tive, the color of the light filter, the density of the specimen, the sensi-
tiveness of the film to the color which the filter transmits and there
are many other factors.

The best way out of the difficulty is to take test photos under
standard conditions, varying the actual time of exposure. After
development of a test film and if the exact data for each exposure have
been recorded, the correct time can easily be determined.

Place the light source at a definite distance from the microscope,
select the filter, record the position of the iris diaphragm in the sub-
stage of the microscope, the magnification and numerical aperture of
the objective, the color and density of the specimen, the magnifying
power of the eyepiece, the type of film used and then take several
exposures, varying the time in wide limits. You can easily find the best
negative. Now maintain these standard conditions for this objective
and only if a specimen of great density is under observation, lengthen
the exposure. Of course, if a different filter is used, new tests have
to be made, unless you know the relative filter factor for the particular
film brand used.

This standardization will undoubtedly be the shortest way to
success and since a microscope equipment will generally not contain
more than three or four objectives and, at the most two or three filters,
the work involved is really negligible, not to speak of the value of
having gone through an experience of this type.

355

Fig. 244 Dental Operating- Room of A. Laurence Dunn, D. D. S., Santa
Barbara, California. Photographed by J. Walter Collinge

(Dr. Dunn is left-handed and the equipment is arranged accordingly)

356

DENTAL -PHOTOGRAPHY

A. LAURENCE DUNN, D.D.S. CHAPTER 20

Dentistry offers one of the finest fields for. the Leica camera in
scientific work. "With it the general practitioner, the specialist, and
the research worker alike will find the opportunity to make records
of a remarkable quality.

To show the many uses in dentistry and in photography of all
small objects, and to explain how the pictures may be obtained with
a minimum of trouble, a simplified yet highly efficient technique is be-
ing offered. The work is divided into three sections dealing first with
the equipment necessary, second the photography itself, and third a
system of records.

Equipment Required

1. Leica camera of any of the later models, and one of the
50 mm lenses such as the Elmar f:3.5, Hektor f:2.5, or
Summar f :2 and a cable release.

2. Fuldy sliding focusing copy attachment.

3. Camera support and reflecting board.

4. Magnifying viewer.

5. Two extension tubes, 12mm and 22mm.

6. Photoflood lamp in reflector.

7. Leicameter.

8. Yard stick.

9. Cardboard backgrounds (black, gray, white, etc.).
10. Eeeord pad and pencil.

One piece of apparatus that greatly simplifies photography at the dental
chair is the camera support, a home-made device. The one shown in figure
245 may serve as a suggestion of what can be constructed to meet individ-
ual needs. Roughly, it consists of a pipe welded onto an old automobile fly-
wheel. Being mounted on casters, it is moved easily, yet stays in position
solidly. It is rolled in place by hand and minor adjustments for position are
made by foot, with one foot on the base.

As the photograph shows, the apparatus is adjustable for every height
and position. The horizontal arm can slide freely on the upright pipe and is
controlled by a thumb screw.

To overcome vibration there are three upright rods welded both to the
flywheel and the upright pipe. The reflecting board is made of an aluminum

357

Fig. 245 Home-made Port-
able Camera Stand sup-
porting Leica camera with
Sliding Focusing Attach-
ment and Eeflector. The
outfit is readily available
for use at the dental
chair. Both Camera and
Reflector are easily ad-
justable, providing- excep-
tional flexibility and ri-
gidity.

cookie sheet. One side of it is kept with a high polish for strong reflections
while the other is dulled slightly by a very fine sand paper or by sand
blasting.

The camera is attached to the horizontal arm by a Leica Ball Jointed
Tripod head. I have found nothing that will take the place of this device in
holding the camera solidly in all positions. Figure 245 shows the construc-
tion of the entire support. It can be made very simply and inexpensively.
The Fuldy copying attachment is described on page 189. It is the ideal
piece of apparatus for accurate viewing and focusing in close work. The
proposed image is seen very clearly on the ground glass back. However, for
the most careful focusing, I strongly urge the addition of the 5x magnifier
and viewer.

358

Dental Photography

For close-up work at least one and preferably two extension tubes are
needed. A serviceable arrangement is to have the 12mm and the 22mm
tubes.

Needless to say, the Weston Leicameter is indispensable. To attempt
to photograph numerous objects under varying light conditions is too hazard-
ous without some means of measuring the light value scientifically.

The Photoflood lamp should be mounted in some handy holder and
reflector. If possible it should be set up close by, to be swung into position
on a moment's notice. At least one spare bulb should be in reserve at all
times. One ingenious way of saving the Photoflood, which burns only two
hours, is to wire it through a Leitz Illumination Control which has seven
degrees of measured light intensity (see page 159). Thus the light can be
reduced to mild brightness for focusing and brought to the desired degree
of intensity for the actual exposure.

Finally, with a yardstick, pencil, and the record pad described in the
third section of this chapter the equipment is ready for use.

A picture of the apparatus set in position is shown in figure 244. When
not in use the outfit is pushed back to the wall and the lamp swung to
the side of the unit. Notice particularly how the camera support with its
camera and reflecting board, and the lamp, are all adjusted in working
position with no interference to the operator. For work in the laboratory
or elsewhere in the room the camera support can easily be rolled into any
position desired.

Making the Photographs

To illustrate the diversity of uses of photography in dentistry
we start first with a series of pictures at the chair, then a series taken
in the laboratory, in research, and in the preparation of papers or
clinics. Many of the ideas presented in this chapter apply equally
well to medicine and surgery and to the photography of all small
objects.

The largest object photographed at the chair is the patient's
face, both front view and profile. This provides a general record, par-
ticularly where any change is to be made in the front of the month.
The main uses are in the young and the old, the children needing
orthodontia and the elderly patients requiring full dentures. Such
a picture will give an accurate record of the conditions to be repro-
duced or eliminated and will serve as a means of comparing the
finished results with the original. Moreover, I feel it to be a very
wise procedure, in this age when so many faces are disfigured in auto-
mobile accidents, to take full face and profile photographs of all
patients.

For these pictures the ideal distance of the camera from the subject is
twenty-two inches.

In most offices the full face picture (fig. 246) can be taken without
electric illumination, daylight being sufficient. Formerly, I used one Photo-
flood with a reflecting board but now seldom use either in the full face
picture. In the profile, help the lighting with one Photoflood and use a black

359

cardboard to serve as a background (fig. 247). Whenever using the aluminum
reflecting board, adjust first the Photoflood light and then the reflecting
board. Place the latter in position to reflect the rays from the Photoflood so
that this secondary illumination will brighten the surfaces not struck directly
by the Photoflood. The technique of adjusting the board is exactly the same
that a small boy uses in annoying the neighbors with a penny mirror on a
sunny day.

Fig. 246 (left) Full face
view, made with Fuldy
C. A. at 22", one second
at f :18

Fig. 247 Profile, same
case, data as above

The Fuldy copying attachment is indispensable for work in dentistry
and close-up photography. In using the Fuldy copying attachment at a
distance beyond 37% inches, difficulty will be encountered from interference
of the collapsible lens mount. This can be overcome as follows: With the
focus lever set at infinity, work the lens into precise focus by sliding it in
and out. Then swing the focus lever down to the opposite limit, 3.5 for
instance. Next slide the camera across, swing the lever back to infinity,
and all will be in proper focus and adjustment.

The next closest picture is that of the anterior teeth (figs. 248-
251). For this put on the 12mm extension tube and bring; the
camera up to approximately nine and a half inches. The distance
from the subject always means the distance measured from the sub-
ject to the back of the camera or the film, and not to the lens. In
this and closer work on patients the Photoflood should be used. Fig-
ure 248 shows a picture in stronger lights and shadows, while figure
249 smoother lighting and less contrast.

A handy retracting device is shown in figures 249, 250 and 251. It is
first formed as desired in wax and then converted into vulcanite. The
method of use for the molar region is shown in figure 251.

Finally where a single tooth, or a group of two or three is desired,
use the 12 mm and the 22 mm together, obtaining a 34 mm extension
tube. Place the camera approximately eight and one-half inches from the
subject. Study pages 198-199 on the decrease in light value with the use of
extension tubes and plan your timing accordingly.

360

Dental Photography

Focusing for Close-Up Objects

Figure 252 is an example of close-up photography. Notice not only
the form and detail of the tooth as reproduced here, but also the bit
of gauze pressed against the right central incisor. Here is an exam-
ple of how a great deal of time and tension can be saved in the care-
ful focusing for close-up work. First cut a small square of gauze

Fig. 248 22mm Tube at 9 %", one
second at f:12.5

Fig. 249 22mm Tube at 9'
second at f :18

from a dental napkin or other loose fabric material. Next select that
position of the field most desired to be in accurate focus. If the field
is flat it will be simpler. If it has considerable depth, as in figure 266
and you have computed what can be gotten into focus, locate a spot

Fig. 250 22mm Tube at 9%", half
second at f:6.3 (overexposed)

251 12mm Tube at 12", one
second at f :18

which will be two-fifths of the way from the front limit toward the
back limit. Place the square of gauze on the selected spot, wherever
it may be, and focus on the gauze instead of any other object in the
field. You will then be focusing on a hair-line instead of a flat
surface.

The preceding pictures have shown how the field can be pro-
gressively diminished and the size of the teeth relatively increased.
Study the usual attachments, distances and lighting for each type of

361

picture, and with but little practice you will soon develop a standard
routine for each.

Tronsillummation of Teeth

Figures 253 and 254 show the effect of transillumination of an
anterior tooth. Here we are confronted with the double problem of
two lighting systems in use simultaneously. This should not be at-
tempted until you have established a standard system of lighting
for your own office which will give you results such as in figures
249 and 252. When that has been worked out to your satisfaction

Fig. 252 12 and 22mm Tubes at
8%", one second at f :18

you are ready to run a series to determine the correct strength for the
trans-illuminating light. First, reduce the main or standard lighting
approximately 30 per cent below normal. I use the Eitter transillu-
minating lamp of the antrum type, as pictured in figure 268. Adjust
it so that it has mild brightness and place it as shown, behind the

Fig. 253 12mm Tube at 17", half
second at f :18

Fig. 254 22mm Tube at 9%", one
second at f :18

tooth. Eecord all factors, and particularly the number shown on the
Eitter rheostat. Then photograph. Next increase the light of the
Eitter lamp by one point and take the next picture. Keep increasing
the voltage one point at a time for approximately five pictures, being
certain to keep accurate records. From the finished results you can
select the one which is to serve as your standard for future pictures.

362

Dental Photography

The next two pictures, figures 255 and 256 are also examples of double
lighting, although in these cases the transilluxninating light is not shining
through the teeth to be operated but onto them, a distant view and a
close-up. Here again the same routine must be worked out as in the pre-
ceding paragraph, a series run to determine the correct balance of lights.

The main thing to bear in mind here is that it must be the Hitter light
and not the standard light that has the correct brilliance. In other words,
the transilluminating light must be such that it will neither over-expose nor
under-expose the negative, while the standard lighting must definitely under-
expose. ^ And let me save time and money for you by again repeating that
effects like these can be obtained only by running a series of exposures and
keeping records.

Fig. 255 12mm Tube at
second at f :5.6

1/20

Fig. 256 22mm Tube at 10%''
half second at f :18

The extent to which the depth of focus can be increased by stopping
down to a small aperture is shown in figures 253 and 255. The former was
taken with the diaphragm closed to f :18, while the latter was opened to
f:5.6. Notice particularly the clearness of the fingers. It is because of
the increase of precise focusing on unimportant details that I prefer to
close the aperture as much as possible. Having selected 18 as my standard
aperture for most work, I can focus through the Fuldy attachment with
the diaphragm wide open at 3.5, then swing the lever to the opposite ex-
treme, or 18, entirely by the sense of touch. Eliminating the necessity of
getting around and viewing the diaphragm reading in close quarters is a
great convenience, and obtaining greater depth of focus is an advantage not
to be overlooked.

Photographing Reflected Images

Another variation from the usual photograph is the one taken
in the mirror. Figures 257 and 258 are two examples. The first is a
picture of the entire vault of the mouth, with an inflamed mucosa
irritated by a full vulcanite denture. The second shows a tooth fol-
lowing the treatment of pyorrhea by the stirgieal method. There are
two precautions for this type of picture. First, the lighting must be
studied very carefully to make sure that the area reflected in the
mirror is as well illuminated as the surrounding non-reflected areas.
It is the latter rather than the former that will determine the light
value 'reading, so be careful. Second, the focusing must be done on

363

the reflected image. It must not be done on the non-reflected front
surface of the object, nor on the glass of the mirror, but on the image
shown in the mirror. With careful holding of the mirror this can
be done as accurately as in the usual pictures.

Fig. 257 12mm Tube at 10", half
second at f :18

Fig. 258 22mm Tube at 9%", one
second at f :18

There is nothing that will take the place of the photograph in
explaining the technique of many operations. Where subject matter
is being prepared for lecture or publication, visual education should
be the first considered. An example of this is shown in the two pic-
tures, figures 259 and 260, where a fixed bridge is being seated with a
rubber dam in position, showing the case before and after the
operation.

Fig. 259 12mm Tube at 13", one
second at f :18

Fig. 260 12mm Tube at 13", one
second at f :18

In figure 261 an interesting method of eliminating background
shadows is shown. Apparently the vulcanite bridge, a Dunn Tempo-
rary Bridge, is suspended in mid-air. The effect is obtained by sup-
porting the object on plate glass and placing the cardboard back-
ground six inches or more below the glass.

At this point it might be well to refer to backgrounds. Strong
cardboards should be on hand for use at. all times, including black,
dark gray, light gray, and white surfaces. Often the background

364

Dental Photography

proves to be the salvation of the picture, especially with the smaller
objects.

Other types of cases are illustrated in succeeding pictures. An unusual
emergency denture repair is pictured in figure 262. Here the points of sig-
nificance from a photographic standpoint are the reproduction of the round-
ness of the porcelain teeth, obtained by a proper lighting, and the great
depth of field, obtained by stopping down to a small diaphragm and timing
accordingly.

Figure 263 illustrates how photography is an aid in the instruc-
tion of cavity preparation. Figure 264 shows plaster models of a case
before and after orthodontic treatment.

Fig. 261 12mm Tube at 9", four Fig. 262 22mm Tube at 10", four

seconds at f :18 seconds at f :18

Determining Exposures

Figure 250 shows the result of a mistake that is apt to be made
very commonly in this type of work, that of over-exposure. Recognize
in measuring the light value in these cases that the teeth form a very
small part of the face and are much lighter than the rest of the face.
For it is not the teeth so much as the skin that determines the Leica-
meter reading. If a photograph is made, based on the Leicameter

Fig. 263 12mm Tube at 12",. two Fig. 264 12mm Tube at 17", two

seconds at f:18 seconds at f:18

reading obtained directly, it will be flat and burned up, as shown in
figure 250. If the time is cut considerably the result will be as in

365

figures 248 and 249. Another suggestion regarding this is told in
connection with figure 264.

One is likely to be deceived as to the true light value of small
objects, particularly where they are very light in color. This is well
demonstrated in the ease of these three plaster models. Placed on
a black background, the greatest light value they would record was
slightly toward 0 from 1. With the Leicameter set for a film with
a speed of 23, the correct camera adjustments were shown to be 13
seconds at aperture 18. However, this was felt to be far beyond
the correct timing.

To determine the correct exposure a large white card of approxi-
mately the same degree of brilliance as the plaster was held in place
just in front of the models and a reading taken of the card. Instead
of slightly less than one, the light value now proved to be 1/6 and
the adjustments this time were changed from 13 seconds at 18, to
V/% seconds at 18. The picture as shown was made with the latter
adjustments.

In your initial work on each new type of case, you will save
time by running a series of pictures, all of the same subject. For
instance, figure 263 was obtained first by finding that the light value
was probably 1/6. Then a small diaphragm, f :18, was chosen in order
to have maLximum depth of focus. Finally a series was run starting at

1 second, then 2, 3, 4, 5, and ending with 6 seconds, but without the
series of pictures I could not have been certain. As originally com-
puted with the aid of the Leicameter reading of the white card, the

2 second exposure proved to be ideal. Again let me urge you always
to run a series of exposures in undertaking a new type of work, then
select the best and use that as standard from then on.

Occasionally there will be a case where the arranging of objects
and studying their most desirable positions is difficult. All of the
plaster models were such examples. The slight turning of one would
throw certain lines in and others out, and the reduced image as
dewed on the ground glass of the Fuldy attachment made adjust-
ment difficult. In such a case place the object in general focus and
approximate arrangement, then slip the camera off of the copy at-
tachment, quickly unscrew the lens and you have an open hole
through which to view. Using it as a frame for your picture, do the
final arranging of the object, then replace the lens and camera and
complete the photography. This aid is seldom needed but can be of
great help in studying arrangement in difficult cases.

Research work can be recorded as shown in figure 265, representing- a
steel die and brass tube testing the precision of a gold casting, and again

366

Dental Photography

in figure 266, a human jaw showing a deep pyorrhea pocket (indicated by
the arrow), and the effect of occlusal attrition.

Other objects which can be photographed are such things as radio-
graphs (fig. 267), collections of interesting dental appliances, the oper-
ator's hand demonstrating a certain technique (fig. 268), and so forth.

Fig. 265 Hollenbeck Tube Dies.
22mm Tube at 9", four seconds at
f:18

Fig. 266 (right) 22mm Tube at
11", four seconds at f:18

The high magnification that can be obtained by the use of extension
tubes is shown in the typodont of gold foil work (figs. 269-271, typodont by
Dr. E. D. Shooshan, Pasadena, Calif.). The picture of the gold foils in the
upper right first molar, the single tooth and the typodont, are all enlarged
to the same degree from their original pictures. The relative enlarging was
done in the photography by means of the tubes, and not in the printing.

The color record of the light pink of condensite material is shown in
this typodont. The color record which vulcanite will give is shown in figure
262. The anterior portion was gum pink and the posterior portion maroon.
Figure 261 also shows maroon vulcanite. No color filters were used.

Fig. 267 22mm Tube at 10", four
seconds at f :18

Fig. 268 22mm Tube at 12", one
second at f :18

In the photographing of small inanimate objects I prefer the soft light
of daylight rather than the artificial illumination of electricity. Figures
261, 263, 264, 266, 271, 269 and 270 were all made without artificial illumina-
tion. The objects were placed on a small stand close to one window. There
was one other window in the room which was used to help modify the
shadows.

367

Some objects, however, require stronger highlights and shadows. These
can be illuminated best with a Photofiood serving- as the spotlight, and day-
light providing the floodlight Figures 262, 265 and 268 are examples of
this type. The lighting of figure 267 was obtained by placing .the radio-
graphic film on a radiographic viewing box.

Fig. 269 12 and 22mm Tubes at
S1^", six seconds at f :18

Fig. 270 9,0, 60, 22 and 12mm
Tubes at 12 W, twelve seconds at
f:22

r-m- '

Fig. 271 12mm Tube
at 9", four seconds at
f:18

Fig. 272 Record stamp

Fig. 273 Print with
record on back

Importance of Keeping Accurate Records

The photographer, who is interested in reproducing rapidly any type
of scene must work out a systematic routine based on accurate records.
This is particularly true of photography in any phase of science, where
close-up apparatus is used and slight variations are of great importance.
Here the subject is frequently a patient and time must be conserved for all
involved.

Following is a routine which will permit check-up and reference:

1. Prepare a pad of paper. With a record stamp (fig. 272), stamp all
sheets on the pad.

2. Place subjects as desired, adjust camera and lighting.

3. Use Leicameter. Determine light value and select correct aperture and
time. '

368

Dental Photography

4. Now STOP • and

RECORD EVERYTHING

5. If planning to take more than one shot of this subject (possibly experi-
menting with varying apertures and timing) record (on chart fig. 273)
EVERY shot in that series, BEFORE TAKING A SINGLE PICTURE.

6. Then photograph AS PLANNED.

Following the development of the film, study It through the Leica film
viewer and marker. By means of this device clip a notch on the border of
the film to designate each picture to be enlarged.

Another method of choosing the pictures to be enlarged is to make
strip prints from the entire film and then make your selection. If you use
this routine be sure to mark the small prints in some suitable manner and in
addition return to the film and clip the notches. This is particularly im-
portant where you have taken a number of test exposures of the same
subject.

Numbers are to be found marking each picture on some brands of
film, while others are blank. Those that are blank should now be numbered
on the film in ink to correspond with the numbers on the last line of the
record chart. Those films which have numbers on the border, will seldom
be found labeled 1-36, but are more apt to be numbered 22-36, 1-21, or 14-36,
1-13, etc. Therefore, these numbers which appear on the film must be re-
corded on the next to bottom line on chart.

When an enlargement (fig. 273) has been printed, turn it over and
stamp the record chart on its back. Then fill in all data found on the
original chart for that print. Now devise some filing system. For mine
I have chosen to paste the pictures on 9" x 12 " sheets of heavy paper that
come in an I-P class G T sectional post binder, top-locking #7717. I have
strip prints made of the entire film and paste those for one film on one
sheet of paper. For quick reference I now write the numbers on the strip
prints, and it is at this point that I mark each print to be enlarged. The
papers carrying the enlargements have the record chart stamped on them
and filled in beneath each enlargement. Any enlargements which are not
mounted are stamped as shown above in figure 273.

It seems a bit safer not to cut the negatives but to store them in the
metal film box. Here they are ready for instant use by referring to the
strip prints.

The result of the above will be a systematic record of all factors in-
volved in obtaining every photograph. When you have a new photograph to
take you can very readily pick out from your file the print most closely
resembling it and proceed by duplicating the recorded factors.

Above all, remember this. Any record routine that is developed
along systematic lines will prove invaluable to anyone anxious for
scientific results. It can be a routine very different from the above
and still be a system. It is not important to copy this one, which
I know works in a highly satisfactory manner and saves time and
money. It is important, however, to develop some routine which is
systematic, accurate and complete.

369

LEICA photos by

Dr. Ramon Castroviejo

Normal Eye.

50mm Summar, f: 1-2.5, 1/20 sec.

Tumor of lower Eye-lid.

50mm Elmar, f:9, 1/8 sec,. 3cm

tube.

Pig-mented Condition of the Eye.
50mm Elmar, f:9, 1/8 sec., 3cm
tube.

Congenital Coloboma of the Iris.

50mm Elmar, f :9, 1/8 sec., 3cm

tube.

Dupont Superior film.

Greater Enlargement of No. 4.

AS AN OPHTHALMIC CAMERA

HENRY M. LESTER CHAPTER 21

Photography of anterior segments of the human eye for scientific
and medical purposes presents problems peculiarly its own. A photo-
graphic camera directed at an eye actually faces another camera,
and a well designed one too, to say the least. Besides this our camera
faces one of the most sensitive and delicate centers of the nerve sys
tern, a very delicate and accurate optical organ and a convex mirror,
photographically speaking: a wide-angle reflecting surface.

To produce photographs of an eye one needs a good camera with
an optical system as flexible as possible. One needs good and suit-
able illumination capable of delivering the light required for short
exposures without unnecessary strain to the eye. One needs fast
films with broad latitude of emulsion and with a full color correction.
And plenty of patience 1

If it is difficult to make precision still photographs of the eye,
it is harder yet to take motion pictures of it. This is particularly
true in cases where the eyes to be photographed are diseased or abnor-
mal, extremely sensitive to light, easily irritated by prolonged ex-
posure to air. Such eyes are usually in motion, almost constantly.
But even if it were possible to immobilize them for a moment the iris
would never remain stationary: the movement of this remarkable
living diaphragm cannot be controlled at will; the size of the aper-
ture, the pupil, is constantly changed as the iris contracts or dis-
tends. Strong light, such as is required for short exposures is almost
invariably unbearable to the eye, causing irritation accompanied by
lacrimination, nervous movements of the eye-ball, eye-lids and the
entire head.

During a recent production of a motion picture dealing with
subnormal vision and describing various optical devices, spectacles
and other aids designed to overcome this handicap, a number of
" close-ups M of eyes (anterior segments) were required to show the
specific condition of the case for which the particular type of
spectacle was being designed. The motion picture was to amplify
a lecture by showing and explaining visually to the profession the
technique of examination of eyes having sub-normal visual acuity, the

371

optical principles underlying the construction of the different types
of telescopic spectacles, pin-hole spectacles, compound magnifiers, con-
tact lenses, etc. The various deformities and anomalies encountered
in cases of sub-normal vision had to be shown to demonstrate available
methods of optical treatments of the different types of defective
vision.

It was felt that it would be useless to expose patients to the
strain, discomfort and hardships of motion picture photography for
close-ups of anterior sections. It was found that "stills" of these
anterior segments, showing the affected eyes in great detail, when
rephotographed on motion picture film yielded all that was desired
and even more, having several advantages. Besides, these "stills7*
were usable for making of lantern slides and also for case history
records.

Fig. 275 Leica mounted on
a Simplex-Pockette 16mm
motion picture camera out-
fit for making still and mo-
tion pictures at the same
time. The author assem-
bled this outfit for his
medical and scientific work

372

Ophthalmic Photography

The entire picture (some 1600 feet of 16mm film) was produced
within eight weeks. Two Simplex-Pockette cameras were used in the
production. Figure 275 shows one of these outfits specially adapted
for this work. The Leica camera was mounted atop the motion
picture camera, where it performed double duty: it was used to
check exposures and general lighting arrangement of each set-up,
and to produce " stills" of every scene quickly, stills that were easily
available, easily reproduced and enlarged to any size desired. This
outfit was used for the general work: long and medium shots. For
close-ups of anterior segments, requiring utmost precision, another
outfit was designed and assembled.

Fig. 276 The Leica as an
Ophthalmic camera

The Leica Equipment

A Leica was mounted upon a heavy compound base of a binocular
ophthalmic microscope. The base, equipped with cross-slide adjust-
able movement was particularly well adapted as a support for the
camera; while extremely rigid it permitted free and fully controlled
movement of the camera in every desired direction for adjustment
and focusing. Thus mounted upon the base the camera was placed
on a heavy adjustable instrument table equipped with an elevating
gear and an adjustable head-and-chin rest. The entire outfit was
very heavy and rigid, permitting accurate and dependable control of
the equipment at all times without being subject to vibrations. The
illustrations show the arrangement as used in detail.

373

The outfit was assembled from the following units and parts :
1. Leica Camera Model F. 2. Lens Shade.

3. Spirit Level. 4. Cable Release.

5. Compound Binocular Microscope Base.

6. Instrument Table with Head and Chin Rest.
1. Sliding Focusing Attachment Model No. 1,

8. Magnifier with adjustable collar for above.

9. Special Attachment Ring (ordinarily used on
the lens when used in the Valoy enlarger).

Two diagonal hair-lines were etched into the surface of the
ground glass of the Focusing Attachment for better centering of the
image. Greater brilliance of the image upon the ground glass was
obtained by rubbing in a drop of oil into the ground side of the glass.

The magnifier not only aided materially in critical focusing, but
also acted in lieu of a focusing cloth, keeping out extraneous light
during focusing on the ground glass. The spirit level was used to
obtain better alignment of the camera with the optical axis of the
eye to avoid distortion. The special attachment ring was used over
the lens to facilitate the operation of the lens diaphragm. It also
served admirably as a lens shade. In addition to the above the fol-
lowing color filters in mounts were used : Panchromatic XI and X2?
Yellow No. 1 and No. 2 and Eed (A).

The optical equipment consisted of the standard Elmar 50mm
f :3.5 lens and the 30mm extension tube. It was found that this lens
has excellent sharpness, correction, definition and resolving power.
This lens, when used in connection with the 30mm extension tube
mounted upon the Sliding Focusing Attachment produced images of
the eye upon the film almost normal size. When set for infinity with
the working distance from the eye being 108 mm the exact ratio of
the size of the object to the size of the image of film is 1 :0.S2.

The Focusing Attachment with the camera connected to it was
mounted upon the compound base by means of a brass key which
fitted into a groove in the head of the base. A set screw tightened
the connection rigidly. This arrangement rendered the camera out-
fit easily interchangeable with the microscope, thus permitting the
use of either at will. It also assured utmost rigidity and freedom
from play and vibration, the importance of which cannot be over-
emphasized.

The outfit having been assembled, considerable experimental work
preceded the actual taking of pictures of cases. The entire procedure
of photographing anterior segments had to be standardized and

374

Ophthalmic Photography

simplified before patients were requested to sit before the camera.
Correct exposures, arrangement of lights, type of film, filters and
many other details had to be worked out and definitely established.

Correct exposures were determined with the Weston Photo-
electric Leicameter. Factors of film, filters, and extension tubes be-
ing known, it was a simple matter to arrive at the correct timing of
the shutter. The factor of the 30 mm tube with the lens set at
infinity is 2.2 x. The lens was usually stopped down to f :9 or f :12.5.
Such small apertures were required to obtain greater depth of focus.
Good definition was obtainable at these apertures of all parts of the
eye, including edges of eye-lids, corners of eye. The maze of capillary
blood vessels of the selera (white, opaque portion of the eye-ball) was
also always in sharp focus. This depth of focus, though not essential
to the picture, imparted usually a feeling of roundness and depth,
with resulting life-like appearance of the eye.

The success of the work depended not only upon a standardized pro-
cedure of the technique of photography, but also on uniformity of materials,
processing and laboratory work. For film the Du Pont Superior Panchro-
matic was selected because of its latitude of emulsion, speed under artificial
light, its color correction, response to filters and its grain structure. All
film was developed, hardened, fixed and washed in Correx tanks. For de-
veloper the well-known Du Pont fine-grain formula was selected: it yielded
fine grain with minimum loss of speed and definition; this formula is known
as Dr. Sease No. 3. (See chapter on Film-Development.)

The use of color filters was avoided as much as possible. Only
where it was absolutely necessary were they put into service. Par-
ticularly, where special colors required it for the purpose of correct
monochromatic rendering the color filters were resorted to. An
example of this is offered in figure 277.

fl Fig. 277 Congenital
Coloboma

Elmar 50mm lens, 30mm
Tube. Photoflash exposure
at f:12.5. DuPont Supe-
rior film. Red (A) filter

375

This photograph showing a case of a congenital coloboma of an eye
was made with the Wratten (A) Eed filter to separate the dark brown
iris from the black pupil. The same photograph made without this
filter showed no appreciable difference between these two colors.

Importance of Focusing

Focusing of the image on ground glass was usually done with
the lens wide open. Subsequently it was stopped down to the desired
aperture. For this work the special Attachment Eing placed on the
front of the lens was almost invaluable. With the eye only 4-5
inches away from the lens, it would have be-en difficult to reset the
lens diaphragm to the desired stop without disturbing the patient.
This ring has outside calibrations, which though not in *kf'; values
are easily memorized as to their equivalents. The patient was placed

Fig. 278 Attachment Eing, which is extremely use-
ful for adjustment of lens diaphragm (Elmar or
Hektor 50mm) in close-up work. It acts also as a
lens shade

comfortably in the chair, the table raised to a level where the lens
of the camera was opposite the eyes, and then the vertical and hori-
zontal fine adjustments were made by means of the rack-and-pinion
of the cross-slide movement of the base. The head of the patient was
made to rest upon the chin rest, after which the focusing was made,
the lights turned on and the exposure quickly made.

Illuminating the Eye

Which brings us to the most trying and difficult problem of
photographing the eye: the illumination. The eye acts as a wide-
angle mirror-like reflecting surface (convex). Not only will it reflect
the light source, but, under certain conditions, the camera and its
operator as well. Photographs of the eye, therefore, should be made
in a room free from illuminated objects or light sources other than
those used for the direct illumination of the eye. There should be
no light entering through the windows, no skylights, nor ceiling
lights. Lights used for illumination should be placed as far as pos-
sible from the eye to render their reflections small and inconspicuous.
Total lack of reflection in the eye is not desirable, because these re-
flections lend the picture of the eye that spark of life, that roundness
and fulness which distinguishes it from a dead eye.

It is difficult to illuminate a normal eye sufficiently for an in-
stantaneous exposure of a small lens aperture. Prolonged exposures

376

Ophthalmic Photography

are undesirable because of the ever-present possibility of movement
of the eye. But there are abnormal, diseased eyes, with all kinds of
lenticular, retinal, corneal involvements, which actually abhor light.
There are cases of Photophobia (which does not mean that they abhor
photographers, although they actually do!); light, even daylight,
hurts them. Their eyes must be shielded, protected from light, and
not exposed to it.

Thus, although the entire process of photographing anterior seg-
ments was standardized sufficiently to form a kind of routine, the
matter of handling, selecting and arranging lights had to be treated
differently in each and every individual case. It had to be made to
suit not only every patient, but the condition of each eye as well;
for there were cases where one eye was entirely different from the
other. Before the patient was placed before the camera, the reaction
of his eyes to light had to be definitely and carefully determined by
the doctor.

Flashlight Eye Exposures

In the case of eyes particularly sensitive to light, the most satis-
factory method of illumination was found in the Photoflash bulb.
The bulb was usually placed in the reflector of a goose-neck type floor
lamp. A diffusion screen was placed before the photoflash bulb; not
so much because of the intensity of the light, but because these bulbs
occasionally crack or break when flashed. The tiny, thin fragments
of glass would be dangerous to the eye of the patient, and one cannot
be too careful in protecting it. The reflector was usually placed some
five to six feet away from the eye, slightly above its level and to one
side of it. On the other side of the eye a white reflecting surface was
placed to provide even illumination, thus imparting roundness to the
picture. Actual focusing was done with the light of a 15-watt bulb,
placed conveniently near the camera. The shutter of the camera was
synchronized with the switch of the bulb; and at the moment sharp
focus was obtained, the exposure was made.

In most instances the patient was barely aware of an intense
light sensation in connection with the flash, which lasts only about
l/50th to l/75th of a second — too short to register any intensity upon
the retina of the eye. To be sure of critical focus, it was at times
necessary to use a special head-and-chin rest for the patient. The rest
was provided with a small piece of flat wood, attached crosswise.
The patient was askod to hold the wood firmly between his teeth dur-
ing focusing, retaining the assumed position for the exposure.

377

Ophthalmic Photography

Eyes with, normal reaction to light were photographed with the
aid of two 500-watt bulbs, or two Photoflood bulbs, in suitable re-
flectors with tracing cloth diff users. The reflectors should not be of
the polished type, but of the oxidized, dull, aluminum finish, to avoid
reflections of filaments upon the subject. One light was placed on
each side of the eye; one closer to it (four to five feet), the other
farther away (six to eight feet). The farther the light source from
the eye the smaller its reflection in the eye. Frequently a white
reflecting surface placed on one side of the eye replaced the second
light, but at some increase in exposure. Focusing was again done
with the light of a low wattage bulb conveniently placed near the
camera and near to the patient's eye.

"Fig. 280 Dr. R. Castroviejo using the Leica for photography
of anterior segments of the eye. Adequate illumination is se-
cured by means of head mirror reflecting powerful spotlight
at time of exposure

Leica for Clinical Photography

I am indebted to Dr. Ramon Castroviejo of the Opthalmic
Institute, Columbia-Presbyterian. Medical Center, New York, for
extremely valuable information and ingenious methods of illumina-
tion of anterior segments of the eye. Dr. Castroviejo assembled
independently a Leica outfit for this work, quite similar to the one
described here, with which he -obtains some remarkable photographs
of anterior segments. He was good enough to demonstrate some
of his work and to permit me to use some of his Leica pictures,

379

which are shown here. Dr. Castro viejo's work is remarkably well
illustrated with Leica photographs, only some of which can be
shown here.

Dr. Castroviejo uses his Leica outfit as an Opthalmic camera
extensively in his clinical work The results of his surgical and
therapeutic treatments of eyes are constantly and periodically
recorded photographically, furnishing a most detailed visual record
for his case histories. Many photographs thus obtained are subse-
quently made into lantern slides, and used in lectures.

Illustrations which follow show the ingenious illumination
methods used by Dr. Castroviejo.

In setting up and operating the Leica Opthalmic equipment Dr.
Castroviejo proceeds as follows:

1. A standard surgical spot-light equipped with a 500-Watt bulb
and a water filter as well as a system of condensing lenses for
focusing and narrowing the beam of light is placed alongside the
patient.

2. The beam of light is directed at the head of the person operating
the camera.

3. The operator wears a head-mirror of the kind used by nose and
throat specialists during examination of interior organs. The
beam of light from the spot-light strikes the mirror and is re-
flected by it in any direction desired.

4. By means of slight movements of the head the operator is in a
position to direct the beam of light upon the eye to be photo-
graphed for as short or as long a time as indicated.

5. The camera is focused as usual, the operator standing behind it
opens the camera shutter and at the same time by a mere nod of
his head makes the beam of light pass quickly across the eye.

6. Directly afterwards the shutter is closed.

7. With a little practice remarkable ease is acquired producing ex-
cellent results with minimum discomfort to the patient. The beam
of light need remain upon the eye a mere fraction of a second.

Another method used by Dr. Castroviejo consists of placing the
same spot-light opposite the patient's eye, alongside the camera, with
the beam directed at the eye. In this case use is made of the compur
shutter with which the spot-light is equipped, controlled by a cable
release. The shutter has speeds of 1/25 to 1/50 of a second. After

380

Ophthalmic Photography

focusing the camera with the aid of a low-wattage bulb, the spot-
light is turned on with the compur shutter remaining closed, but set.
for the desired speed. Opening the shutter of the camera, releasing
the shutter of the spot-light, and closing the shutter of the camera,
takes less time than to say it ! The illustrations show details of these
various set-ups.

Use of the Placido Disc

Several photographs were required of eyes with deformities of
the cornea. The cornea (the outer transparent part of the eye-ball;
of a normal eye is spherical, forming a segment of a sphere slightly
smaller in diameter than that of the eye-ball itself. It is smooth and
glossy. Its roundness and smoothness enable it to act as a convex
reflecting surface. In some cases the cornea assumes shapes different
from normal, sometimes resembling a cone, in other cases it develops
deformities of the outer surface, irregularities of the curvature,
wrinkles, etc. All of these deformities result in distorted and defec-
tive vision. Some of them are very slight, however, barely visible to
the eye. The fact that a normal cornea acts as a convex mirror had
been utilized in the detection of these irregularities and in their
accurate measurement. A white disc (known as the Placido Disc),
some 12 to 18 inches in diameter, upon which had been drawn con-
centric black circles about 1 inch wide and about 1 inch apart, is
placed in front of the eye. Through an aperture in the center of the
disc one can observe the reflection of this disc in the eye. A normal
cornea will reflect a true reduced image of these concentric black and
white circles, fully retaining their roundness, spacing and concen-
tricity. A malformed cornea will reflect a distorted image, from the
nature, shape and direction of which the character of the malforma-
tion can be diagnosed and measured.

Fig. 281 Placido Disk Reflection in Cornea Fig. 282 Placido Disk Reflection in Cornea

of Normal Eye of Diseased Eye

381

To obtain photographs of reflections of Placido Discs in normal
and in abnormal eyes the same Leica outfit was used, but the illumina-
tion was changed. A Placido Disc was placed over the lens, which
was accomplished by inserting into its center aperture a black paper
tube (about 2" long), which in turn was slipped over the Leica lens.
The black paper tube acted as an extended lens hood. The center of
the Placido Disc was made to coincide approximately with the optical
axis of the lens. Two 500-watt bulbs in reflectors were placed slightly
behind the patient and the light was directed at the Placido Disc.
The light reflected from the white portions of the disc served to
illuminate the eye. In arranging the lights care was taken to prevent
direct rays of light from striking the elements of the lens. The fol-
lowing illustrations show a photbigiraph of a normal eye and that of
an eye with a distorted, malformed cornea.

Portraits of Patients

The flexibility of this Leica outfit made it possible to use it for still
another purpose. By simply removing the 30mm extension tube and mount-
ing the 50mm lens directly upon the sliding focusing attachment one se-
cured a portrait view camera with a ground glass upon which to compose
the picture. Focusing- in this case was accomplished by unlocking the lens
barrel of the Elmar 50mm lens (turning it counter-clockwise) and moving
it in and out. Portraits of patients were wanted for case
histories and records to show the marked difference
in facial expressions resulting from improved vision.
The tired, haggard and tense expression typical of a
patient during his early examinations was usually su-
perseded by an expression of ease and contentment
after the correct spectacles were fitted. For this pur-
pose photographs of the head and a portion of the
shoulders were wa'nted. Fo.r photographs of anterior
segments the patient was asked to lean forward in
his chair and' to rest his head upon the chin rest. For
portraits the same patient was asked to lean upon the
back of the chair. The change in the focal length of
the lens, produced .by the removal of the extension
to^ra2!3 ?fcorp5h°" tube> permitted making these two different pictures
w!anpng Pin-hofe 1<m without moving the camera, nor for that matter dis-
Spectacies turbing the patient, who did not have to leave the chair.

Subsequently a system of records .of cases was developed consisting of
mounting on the back of history cards pictures showing the patient at first
examination, anterior segments of his eyes, and a photograph of the
patient wearing spectacles designed for him. A photograph of such a
portrait is shown here.

The usefulness of this Leica outfit did not stop after the comple-
tion of photographs of anterior segments and portraits of patients.
Another phase of the motion picture work offered great difficulties

382

Ophthalmic Photography

and again the Leica was put to work and successfully used as a short-
cut. In explaining the principles underlying the construction and
design of various spectacles used as aids to eyes affected with sub-
normal vision it was desired to show how a beam of light is refracted
in passing through the medium of a lens, what happens to it when it
enters the eye, and how the path of this beam of light can be con-
trolled to produce an image upon the retina by making it pass through
certain media before entering the eye.

Smoke Box Photography

A schematic model of the eye was built of glass. Also a special
"smoke box", consisting of a wooden box, painted with dead black
coating inside. One of the sides of the box was fitted with plate glass,
which enabled observation from the outside. At one of the ends an
opening was made through which a, beam of light could be admitted.
An optical bench was placed inside the box, and various lenses, slits,
prisms, pin-holes and similar media were mounted upon it aligned
along the same optical axis. A strong source of light-was placed on
the outside of the box with the beam light entering the box through
the side opening. The bunch of rays entering the box was made as
nearly parallel as possible. When the box was filled with smoke the
path of rays became plainly visible in a darkened room. The rays
were made to pass through lenses, prisms, slits, pin-holes, etc., and as
a result were made to converge, diverge, change direction, intensity,
etc. At the end of considerable experimentation to produce the de-
sired results this turned out to be an interesting and quite a dramatic
spectacle. But the motion picture camera was blind to it, despite fast
lenses and fast films! Although a very strong source of light was

Fig, 284 Smoke Box photograph showing behavior of bundle of rays
after passing through convex lens

Elmar 50mm lens. Three • minutes ' at f:18. DuPont Superior film. Bed (A) filter

383

used, its actinic value was slight. Because what we saw was, of course,
not light itself, but merely the illuminated minute particles of smoke,
which reflected less light the farther away they were from its source.
To intensify these illuminated particles, a bit of powdered chalk was
shaken into the smoke box just before the exposure was made.

The Leica was used to record these set-ups. When enlarged these
photographs were rephotographed on motion picture film, producing
results which were found to be excellent in every way. The camera
mounted upon its rigid support described previously was as free from
vibration as possible. This was important because very long expos-
ures were required : with the lens stopped down to f :18 and with a
red (A) filter used to retard the light and to bring out some detail
in the shadows of the set-up and equipment inside the smoke-box —
the exposures ranged from 2 to 5 minutes ! The following illustrations
show these actual photographs/obtained in this manner and subse-
quently incorporated into the motion picture film.

Fig. 285 Smoke Box photograph

showing behavior of bundle of rays after passing through simple "telescope", entering
model of eye and forming image upon retina. Exposure as in Fig. 284

These photographs had to be produced in a darkened room. All
those present in the room had to remain motionless throughout the
long exposures. To prevent vibration caused by street traffic and
subways the actual exposures were made between 2 A. M. and 5 A. M.

When reproductions of these photographs were later flashed upon
a screen as a part of the motion picture they appeared just as real as
if they were produced directly upon the moving film, there being no
action, but merely an even and steady flow of light, i Thus these stills
were just as effective, but much, much simpler to make than by means
of a " stop-mo tion" mechanism on the motion picture camera. Gor-

384

Ophthalmic Photography

rect exposures for these photographs were obtained by the tedious,
But infallible method of trial-and-error. Exposures varied with every
set-up because of various light intensities resulting from the use of
various media through which the light was made to pass. The prepa-
ration of each set-up was so tedious that some three to six shots of
each were made : just to play safe.

Fig. 286 Smoke Box photograph

showing- bundle of rays entering model of eye rendered defective by simulated corneal
opacities. No image formed upon retina. Exposure as in Fig. 2$4

At the conclusion of this work literally hundreds of feet of Leica
film were on hand. These were scrutinized carefully, the best ones
chosen, classified, viewed through the enlarger. Test prints were
made, and unessential portions of photographs masked out.

Glossy 5x7 prints, f errotyped, were made of all photographs
desired for the motion picture work. They were uniform in size,
finish, all were arranged and centered correctly. Mounted upon a
special easel these prints were photographed with the Simplex Pock-
ette camera in such a way that the white borders did not show.

"When these " stills" were subsequently projected on a 7 x 9 foot
screen they appeared amazingly life-like, brilliant and possessing all
the roundness and detail that could be desired. What is more, as far
as showing anterior segments was concerned, these stills had many
advantages over actual direct shots : each eye stood still, as if caught
and stopped; it was wide open for leisurely examination and observa-
tion of its defects and details. There was no contraction of the iris,
no movement of eye-lids to obscure portions of the eye-ball, there was
no visible trace of effort on the part of the patient to show it, no
lacrimation nor discoloration, which usually are caused by prolonged
examination of the eye.

385

Lightning Striking Empire State

John P. Gaty

Ehnar 90mm lens, Time Exposure at f :4, DuPont Infra-D film, Wratten C and F filters

386

JOHN P. GATY CHAPTER 22

Photography by means of light beyond the ends of the visible
spectrum offers many interesting possibilities to the experimenter.
Ultra-violet photography, using shorter wave lengths than those trans-
mitted by optical glass, requires expensive quartz lenses and filters
which are not available to the average photographer. The invisible
light of the extreme red and infra-red region, which consists of
longer wave lengths than the visible red light, can be utilized for
photography without the aid of expensive auxiliary equipment. A
minimum investment in this type of experiment would be the pur-
chase of a roll of infra-red sensitive film and a red gelatine filter.
The ordinary Leica lens of any type will work perfectly, although the
Elmar series should be set at a scale reading of 100 feet in order to
focus the infra-red rays from distant objects. The Hektor series
requires slightly less compensation, while the latest Summar lens is
provided with a special index mark on the mount for the purpose
of focusing with infra-red.

If close-ups are required, adjust the lens to the true distance
and then subtract the same amount of angular rotation as was re-
quired to move the lens from the true infinity position to the selected
infra-red infinity position. This amount of angular rotation is
measured on the circular edge of the focusing ring. In all cases
the infra-red scale-reading will be less than the panchromatic scale-
reading, by a very slight amount. Images formed by infra-red rays
focus slightly further back of the focal plane formed by visible light.
To compensate for this generally slight difference, the lens should be
racked out by something like 1/200 of its focal length. Thus, if a
50mm lens is used for infra-red photography, it should be racked
out about %mm. In most eases the correction for close-ups is un-
necessary, due to the depth of focus of the lens.

It is rather difficult to visualize the nature of infra-red rays. The
fact that the word red is made part of its name should not be taken
to imply that these rays are colored red. The name of these rays
implies merely that they can be located in the spectroscope in the

387

region adjoining red. Because the human eye is not sensitive to
infra-red rays it should not be even taken as light. They can be
most accurately described as invisible rays. It is quite possible to
describe infra-red rays as heat rays.

The use of infra-red light for photography is not new. Almost
one hundred years ago Herschel made infra-red photographs by in-
direct methods which are still used to explore the infra-red regions
beyond the range of response of our most modern emulsions. Hersehel
discovered that an emulsion which has been exposed to blue light
will show a diminution of exposure wherever it is exposed to red
or infra-red rays. A film which has been uniformly fogged by blue
light will then show a positive image of a subsequently made infra-
red exposure, when it is developed. Patience and careful control
are required to make this system work effectively, but it offers great
possibilities for research in regions otherwise beyond the reach of
photography.

Infra-Red Films

Modern infra-red photography dates from about 1910 when the
experiments of Professor E. W. Wood were announced to world
famous scientific organizations. For a time popular interest lagged,
due to the difficulty of obtaining suitable emulsions. Recently, great
progress toward perfection of infra-red sensitive materials has
brought the amateur photographer stable and fairly sensitive emul-
sions suitable for the purpose. Those available for the Leica are
Agfa R film, DuPont Infra-D film and Eastman K film. The DTI-
Pont Infra-D and the Agfa E films are especially spooled for the
Leica and are available from all dealers.

It is extremely important to use, whenever possible, extremely
fresh material that is sensitized to infra-red light. Fresh films will
be found more sensitive than old. It loses its sensitivity in a com-
paratively short time. Infra-red film six months old is generally
half of its original speed at the time of production. It is therefore
recommended that infra-red film be secured with an indication as
to when it was produced at the factory.

The special applications of infra-red photography depend on
two main characteristics of infra-red light. First: it has unusual
power of penetration of atmospheric haze and certain materials
which are opaque to visible light. Second: many substances show a
reflective power to infra-red light which has no apparent relation
to their reflective power to visible light. The full range of wave
lengths of infra-red light is considered to be about three thousand

388

Infra-Red

times as great as the full range of the total visible spectrum from
violet to deep red. In other words, if the total visible color spectrum
were considered as a piano keyboard, with each note representing
a different wavelength band, or color, it would take a piano with
three thousand progressively arranged keyboards to contain all the
notes or colors in the infra-red spectrum. Photographically, only
the very beginning of this composite keyboard has been explored to
date, since most experimenters have failed to reach further than the
top of the fourth standard keyboard length above the visible spec-
trum. The films already listed reach approximately to the top of the
first standard keyboard length above the end of the visible spectrum,
but in this region alone there lies a complete gamut of invisible colors
(if such a thing can be) . Since these cannot be seen, their effect on
the infra-red sensitive film must be determined by experiment.

For illustration: some black, green, olive, blue, and violet dyes
will photograph as light gray or almost white under certain wave-
lengths of infra-red light. Other dyes matching exactly in visible
color will photograph by the same light as dead black or dark gray.
This fact may lead to adoption of specialized infra-red and heat re-
fleeting dyes for summer clothing. The cloth would appear to be
dark to the eye and would not soil readily, but would be as cool to
wear as a white garment.

Differences in. Infra-Red Values

These two fundamental characteristics of atmospheric penetra-
tion and unusual tonal response are the causes of the peculiar effects
depicted in landscapes when they are photographed by infra-red
light. On a clear day there is a total lack of atmospheric perspective,
or the demarcation of various planes in the distance due to the sepa-
ration of tones by atmospheric haze. The foliage of most trees reflects
infra-red light perfectly and the sunlit trees appear in the photo-
graph to be covered with silver leaves. This effect is greater

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Full text of "The Leica Manual A Manual For The Amateur And Professional Covering The Entire Field Of Leica Photography"

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